Fix PairRDDFunctions.groupWith partitioning
Fix PairRDDFunctions.groupWith partitioning

This commit fixes a bug in groupWith that was causing it to destroy
partitioning information. It replaces a call to map with a call to
mapValues, which preserves partitioning.

lyogavin/spark,techaddict/spark,rednaxelafx/apache-spark,shaneknapp/spark,janewangfb/spark,markhamstra/spark,HyukjinKwon/spark,eyalfa/spark,ajaysaini725/spark,jkbradley/spark,kiszk/spark,jiangxb1987/spark,nlalevee/spark,apache-spark-on-k8s/spark,jianran/spark,ahnqirage/spark,lvdongr/spark,sureshthalamati/spark,andrewor14/spark,lvdongr/spark,wzhfy/spark,poffuomo/spark,wangmiao1981/spark,adrian-ionescu/apache-spark,ron8hu/spark,ptkool/spark,SHASHANKB/spark,panfengfeng/spark,JerryLead/spark,cloud-fan/spark,ConeyLiu/spark,techaddict/spark,srowen/spark,ptkool/spark,narahari92/spark,zero323/spark,jrshust/spark,javelinjs/spark,rikima/spark,narahari92/spark,shubhamchopra/spark,bravo-zhang/spark,zzcclp/spark,milliman/spark,shubhamchopra/spark,cloud-fan/spark,shubhamchopra/spark,mike0sv/spark,SnappyDataInc/spark,caneGuy/spark,szhem/spark,shuangshuangwang/spark,BryanCutler/spark,ioana-delaney/spark,rednaxelafx/apache-spark,stanzhai/spark,wangyum/spark,rjpower/spark,jlopezmalla/spark,jianran/spark,huang1900/spark,cloud-fan/spark,highfei2011/spark,loneknightpy/spark,witgo/spark,zhouyejoe/spark,zuotingbing/spark,SHASHANKB/spark,actuaryzhang/spark,ajaysaini725/spark,publicRoman/spark,ConeyLiu/spark,wangmiao1981/spark,narahari92/spark,metamx/spark,darionyaphet/spark,tejasapatil/spark,ankurdave/arthur,techaddict/spark,maropu/spark,stanzhai/spark,setjet/spark,publicRoman/spark,dbtsai/spark,kiszk/spark,wangmiao1981/spark,kissmetrics/spark,vax11780/spark,setjet/spark,ddna1021/spark,dongjoon-hyun/spark,tejasapatil/spark,janewangfb/spark,goldmedal/spark,dbtsai/spark,apache-spark-on-k8s/spark,janewangfb/spark,caneGuy/spark,andrewor14/iolap,JerryLead/spark,lxsmnv/spark,ddna1021/spark,sryza/spark,akopich/spark,actuaryzhang/spark,kissmetrics/spark,icexelloss/spark,gengliangwang/spark,big-pegasus/spark,SnappyDataInc/spark,UndeadBaneGitHub/spark,kimoonkim/spark,highfei2011/spark,andrewor14/spark,kimoonkim/spark,brad-kaiser/spark,rezasafi/spark,jlopezmalla/spark,debugger87/spark,shuangshuangwang/spark,esi-mineset/spark,saturday-shi/spark,ron8hu/spark,eyalfa/spark,ericvandenbergfb/spark,andrewor14/iolap,akopich/spark,liyichao/spark,tejasapatil/spark,rekhajoshm/spark,JoshRosen/spark,lxsmnv/spark,nlalevee/spark,rednaxelafx/apache-spark,pgandhi999/spark,apache/spark,milliman/spark,mzl9039/spark,cin/spark,caneGuy/spark,hvanhovell/spark,gioenn/xSpark,apache-spark-on-k8s/spark,srowen/spark,hhbyyh/spark,alunarbeach/spark,yanboliang/spark,haowu80s/spark,huang1900/spark,narahari92/spark,eyalfa/spark,BryanCutler/spark,goldmedal/spark,aray/spark,wgpshashank/spark,skonto/spark,loneknightpy/spark,darionyaphet/spark,shaneknapp/spark,markhamstra/spark,ioana-delaney/spark,aokolnychyi/spark,Panos-Bletsos/spark-cost-model-optimizer,loneknightpy/spark,holdenk/spark,ahnqirage/spark,mahak/spark,lvdongr/spark,jiangxb1987/spark,lyogavin/spark,LantaoJin/spark,jrshust/spark,narahari92/spark,WindCanDie/spark,liyichao/spark,icexelloss/spark,michalsenkyr/spark,kiszk/spark,nilsgrabbert/spark,BryanCutler/spark,gioenn/xSpark,pronix/spark,mike0sv/spark,holdenk/spark,xuanyuanking/spark,janewangfb/spark,ioana-delaney/spark,HyukjinKwon/spark,lxsmnv/spark,akopich/spark,adrian-ionescu/apache-spark,kimoonkim/spark,skonto/spark,hhbyyh/spark,debugger87/spark,patrick-nicholson/spark,sachintyagi22/spark,chuckchen/spark,kimoonkim/spark,ddna1021/spark,someorz/spark,publicRoman/spark,stanzhai/spark,ibm-research-ireland/sparkoscope,liyichao/spark,nchammas/spark,mkolod/incubator-spark,byakuinss/spark,eyalfa/spark,Panos-Bletsos/spark-cost-model-optimizer,wangyum/spark,zhouyejoe/spark,zuotingbing/spark,cloudera/spark,szhem/spark,zuotingbing/spark,wzhfy/spark,vinodkc/spark,esi-mineset/spark,sahilTakiar/spark,ibm-research-ireland/sparkoscope,dbtsai/spark,apache/spark,dongjoon-hyun/spark,saturday-shi/spark,loneknightpy/spark,yanboliang/spark,publicRoman/spark,wangyum/spark,highfei2011/spark,publicRoman/spark,ptkool/spark,dbtsai/spark,ericvandenbergfb/spark,aray/spark,nlalevee/spark,apache/spark,aosagie/spark,bravo-zhang/spark,xuanyuanking/spark,JerryLead/spark,saturday-shi/spark,debugger87/spark,publicRoman/spark,panfengfeng/spark,map222/spark,icexelloss/spark,jkbradley/spark,darionyaphet/spark,haowu80s/spark,someorz/spark,shuangshuangwang/spark,stanzhai/spark,dongjoon-hyun/spark,taroplus/spark,sachintyagi22/spark,metamx/spark,sureshthalamati/spark,poffuomo/spark,MLnick/spark,bdrillard/spark,jperla/spark-advancers,wzhfy/spark,gioenn/xSpark,ptkool/spark,1haodian/spark,shuangshuangwang/spark,liyichao/spark,kimoonkim/spark,milliman/spark,szhem/spark,zero323/spark,rikima/spark,facaiy/spark,SHASHANKB/spark,nilsgrabbert/spark,sachintyagi22/spark,milliman/spark,cloudera/spark,minixalpha/spark,aosagie/spark,witgo/spark,gioenn/xSpark,taroplus/spark,lyogavin/spark,saltstar/spark,mzl9039/spark,apache/spark,ibm-research-ireland/sparkoscope,apache-spark-on-k8s/spark,dbtsai/spark,skonto/spark,spark-test/spark,UndeadBaneGitHub/spark,rekhajoshm/spark,map222/spark,tejasapatil/spark,gioenn/xSpark,cloudera/spark,setjet/spark,akopich/spark,saltstar/spark,icexelloss/spark,bravo-zhang/spark,rikima/spark,mahak/spark,shaneknapp/spark,mahak/spark,janewangfb/spark,jianran/spark,panfengfeng/spark,zzcclp/spark,mahak/spark,maropu/spark,pronix/spark,vinodkc/spark,lyogavin/spark,zero323/spark,sryza/spark,holdenk/spark,kevinyu98/spark,yanboliang/spark,cloud-fan/spark,saturday-shi/spark,minixalpha/spark,brad-kaiser/spark,pronix/spark,dotunolafunmiloye/spark,holdenk/spark,milliman/spark,jlopezmalla/spark,rjpower/spark,nlalevee/spark,sureshthalamati/spark,joseph-torres/spark,dongjoon-hyun/spark,sachintyagi22/spark,milliman/spark,xflin/spark,Aegeaner/spark,jrshust/spark,bOOm-X/spark,facaiy/spark,nlalevee/spark,alunarbeach/spark,rednaxelafx/apache-spark,metamx/spark,LantaoJin/spark,Aegeaner/spark,MLnick/spark,witgo/spark,rekhajoshm/spark,liutang123/spark,metamx/spark,alunarbeach/spark,LantaoJin/spark,yanboliang/spark,rjpower/spark,big-pegasus/spark,dotunolafunmiloye/spark,adrian-ionescu/apache-spark,sahilTakiar/spark,huang1900/spark,wzhfy/spark,goldmedal/spark,brad-kaiser/spark,jrshust/spark,bravo-zhang/spark,vinodkc/spark,poffuomo/spark,someorz/spark,nilsgrabbert/spark,zuotingbing/spark,chuckchen/spark,wgpshashank/spark,WeichenXu123/spark,aray/spark,ptkool/spark,patrick-nicholson/spark,yanboliang/spark,icexelloss/spark,cin/spark,chuckchen/spark,rikima/spark,ueshin/apache-spark,liyichao/spark,darionyaphet/spark,wangyum/spark,dbtsai/spark,haowu80s/spark,BryanCutler/spark,stanzhai/spark,skonto/spark,wzhfy/spark,guoxiaolongzte/spark,ankurdave/arthur,jiangxb1987/spark,nilsgrabbert/spark,bOOm-X/spark,jkbradley/spark,tejasapatil/spark,liutang123/spark,rekhajoshm/spark,pgandhi999/spark,kissmetrics/spark,chuckchen/spark,bravo-zhang/spark,tengpeng/spark,nlalevee/spark,sachintyagi22/spark,dhruve/spark,zzcclp/spark,spark-test/spark,bOOm-X/spark,kiszk/spark,hhbyyh/spark,Aegeaner/spark,setjet/spark,spark-test/spark,spark-test/spark,sachintyagi22/spark,aokolnychyi/spark,andrewor14/spark,zhouyejoe/spark,cin/spark,hvanhovell/spark,brad-kaiser/spark,adrian-ionescu/apache-spark,ahnqirage/spark,guoxiaolongzte/spark,JoshRosen/spark,dhruve/spark,andrewor14/spark,metamx/spark,1haodian/spark,mike0sv/spark,kevinyu98/spark,nchammas/spark,tengpeng/spark,witgo/spark,ron8hu/spark,ahnqirage/spark,dongjoon-hyun/spark,markhamstra/spark,zzcclp/spark,rezasafi/spark,LantaoJin/spark,facaiy/spark,someorz/spark,nchammas/spark,HyukjinKwon/spark,lxsmnv/spark,hhbyyh/spark,icexelloss/spark,apache-spark-on-k8s/spark,wangyum/spark,nilsgrabbert/spark,xflin/spark,mahak/spark,kevinyu98/spark,UndeadBaneGitHub/spark,jianran/spark,skonto/spark,1haodian/spark,goldmedal/spark,ddna1021/spark,zzcclp/spark,guoxiaolongzte/spark,ankurdave/arthur,jlopezmalla/spark,JerryLead/spark,milliman/spark,nlalevee/spark,nchammas/spark,caneGuy/spark,wangyum/spark,adrian-ionescu/apache-spark,saturday-shi/spark,andrewor14/iolap,gengliangwang/spark,xuanyuanking/spark,cin/spark,andrewor14/iolap,JerryLead/spark,xuanyuanking/spark,srowen/spark,big-pegasus/spark,minixalpha/spark,darionyaphet/spark,saltstar/spark,setjet/spark,ericvandenbergfb/spark,andrewor14/spark,SHASHANKB/spark,pronix/spark,actuaryzhang/spark,liyichao/spark,techaddict/spark,dhruve/spark,rjpower/spark,jiangxb1987/spark,sureshthalamati/spark,taroplus/spark,patrick-nicholson/spark,mdespriee/spark,maropu/spark,ericvandenbergfb/spark,guoxiaolongzte/spark,bOOm-X/spark,esi-mineset/spark,chuckchen/spark,pronix/spark,rednaxelafx/apache-spark,MLnick/spark,kiszk/spark,JoshRosen/spark,LantaoJin/spark,UndeadBaneGitHub/spark,dongjoon-hyun/spark,ericvandenbergfb/spark,shubhamchopra/spark,JoshRosen/spark,eyalfa/spark,dbtsai/spark,mdespriee/spark,kiszk/spark,xuanyuanking/spark,mdespriee/spark,SnappyDataInc/spark,sachintyagi22/spark,ibm-research-ireland/sparkoscope,zero323/spark,kimoonkim/spark,darionyaphet/spark,pgandhi999/spark,guoxiaolongzte/spark,LantaoJin/spark,kissmetrics/spark,nchammas/spark,wangmiao1981/spark,Panos-Bletsos/spark-cost-model-optimizer,cloud-fan/spark,rezasafi/spark,sryza/spark,lvdongr/spark,zhouyejoe/spark,ahnqirage/spark,pgandhi999/spark,apache-spark-on-k8s/spark,WeichenXu123/spark,kevinyu98/spark,patrick-nicholson/spark,Panos-Bletsos/spark-cost-model-optimizer,jiangxb1987/spark,rezasafi/spark,Aegeaner/spark,UndeadBaneGitHub/spark,caneGuy/spark,sryza/spark,rekhajoshm/spark,andrewor14/iolap,mzl9039/spark,dotunolafunmiloye/spark,xflin/spark,aosagie/spark,witgo/spark,hhbyyh/spark,ibm-research-ireland/sparkoscope,zhouyejoe/spark,ueshin/apache-spark,apache/spark,rednaxelafx/apache-spark,aosagie/spark,MLnick/spark,ConeyLiu/spark,byakuinss/spark,sureshthalamati/spark,actuaryzhang/spark,tengpeng/spark,jianran/spark,jlopezmalla/spark,poffuomo/spark,alunarbeach/spark,sahilTakiar/spark,mike0sv/spark,maropu/spark,sryza/spark,gengliangwang/spark,WeichenXu123/spark,darionyaphet/spark,bOOm-X/spark,bdrillard/spark,mzl9039/spark,panfengfeng/spark,markhamstra/spark,debugger87/spark,ankurdave/arthur,joseph-torres/spark,wangyum/spark,mdespriee/spark,sahilTakiar/spark,saturday-shi/spark,goldmedal/spark,tengpeng/spark,kimoonkim/spark,esi-mineset/spark,vax11780/spark,yanboliang/spark,rekhajoshm/spark,koeninger/spark,techaddict/spark,ajaysaini725/spark,sahilTakiar/spark,hvanhovell/spark,taroplus/spark,rjpower/spark,mike0sv/spark,patrick-nicholson/spark,hvanhovell/spark,HyukjinKwon/spark,zzcclp/spark,spark-test/spark,haowu80s/spark,UndeadBaneGitHub/spark,saltstar/spark,ueshin/apache-spark,loneknightpy/spark,holdenk/spark,MLnick/spark,vax11780/spark,patrick-nicholson/spark,actuaryzhang/spark,cin/spark,lyogavin/spark,HyukjinKwon/spark,holdenk/spark,wangmiao1981/spark,rezasafi/spark,LantaoJin/spark,zero323/spark,pgandhi999/spark,mdespriee/spark,wangmiao1981/spark,wangmiao1981/spark,pgandhi999/spark,lvdongr/spark,xflin/spark,1haodian/spark,debugger87/spark,koeninger/spark,Panos-Bletsos/spark-cost-model-optimizer,cin/spark,UndeadBaneGitHub/spark,gioenn/xSpark,bdrillard/spark,tengpeng/spark,kevinyu98/spark,cin/spark,zhouyejoe/spark,alunarbeach/spark,ajaysaini725/spark,caneGuy/spark,hhbyyh/spark,1haodian/spark,andrewor14/spark,dhruve/spark,map222/spark,szhem/spark,hhbyyh/spark,sureshthalamati/spark,wzhfy/spark,ericvandenbergfb/spark,ddna1021/spark,ron8hu/spark,saltstar/spark,jiangxb1987/spark,witgo/spark,xflin/spark,liutang123/spark,jlopezmalla/spark,joseph-torres/spark,ueshin/apache-spark,actuaryzhang/spark,huang1900/spark,JoshRosen/spark,alunarbeach/spark,michalsenkyr/spark,jkbradley/spark,stanzhai/spark,shuangshuangwang/spark,zuotingbing/spark,esi-mineset/spark,ahnqirage/spark,koeninger/spark,vinodkc/spark,saltstar/spark,loneknightpy/spark,dotunolafunmiloye/spark,metamx/spark,michalsenkyr/spark,1haodian/spark,WindCanDie/spark,jianran/spark,pronix/spark,cloudera/spark,liutang123/spark,markhamstra/spark,huang1900/spark,mzl9039/spark,tengpeng/spark,ajaysaini725/spark,akopich/spark,goldmedal/spark,mzl9039/spark,WindCanDie/spark,WeichenXu123/spark,jkbradley/spark,nilsgrabbert/spark,ahnqirage/spark,panfengfeng/spark,liutang123/spark,SnappyDataInc/spark,highfei2011/spark,map222/spark,aokolnychyi/spark,WindCanDie/spark,saltstar/spark,SHASHANKB/spark,rikima/spark,mkolod/incubator-spark,minixalpha/spark,witgo/spark,map222/spark,BryanCutler/spark,taroplus/spark,gengliangwang/spark,WindCanDie/spark,mkolod/incubator-spark,michalsenkyr/spark,minixalpha/spark,HyukjinKwon/spark,haowu80s/spark,poffuomo/spark,aokolnychyi/spark,xflin/spark,vinodkc/spark,1haodian/spark,ron8hu/spark,dhruve/spark,szhem/spark,gengliangwang/spark,panfengfeng/spark,cloud-fan/spark,szhem/spark,WeichenXu123/spark,someorz/spark,shaneknapp/spark,adrian-ionescu/apache-spark,dhruve/spark,WindCanDie/spark,zuotingbing/spark,SnappyDataInc/spark,jrshust/spark,WindCanDie/spark,publicRoman/spark,ajaysaini725/spark,BryanCutler/spark,shubhamchopra/spark,apache/spark,shaneknapp/spark,JoshRosen/spark,cloud-fan/spark,xuanyuanking/spark,shubhamchopra/spark,byakuinss/spark,rednaxelafx/apache-spark,apache-spark-on-k8s/spark,shaneknapp/spark,holdenk/spark,panfengfeng/spark,zero323/spark,eyalfa/spark,chuckchen/spark,mahak/spark,SHASHANKB/spark,aosagie/spark,michalsenkyr/spark,joseph-torres/spark,markhamstra/spark,map222/spark,stanzhai/spark,mdespriee/spark,mdespriee/spark,kiszk/spark,shaneknapp/spark,maropu/spark,SnappyDataInc/spark,narahari92/spark,byakuinss/spark,lvdongr/spark,zzcclp/spark,techaddict/spark,jiangxb1987/spark,caneGuy/spark,HyukjinKwon/spark,sahilTakiar/spark,brad-kaiser/spark,byakuinss/spark,zuotingbing/spark,nilsgrabbert/spark,ConeyLiu/spark,janewangfb/spark,saturday-shi/spark,nchammas/spark,setjet/spark,sahilTakiar/spark,jlopezmalla/spark,ioana-delaney/spark,alunarbeach/spark,kissmetrics/spark,Panos-Bletsos/spark-cost-model-optimizer,WeichenXu123/spark,ron8hu/spark,koeninger/spark,dhruve/spark,shuangshuangwang/spark,ddna1021/spark,Aegeaner/spark,adrian-ionescu/apache-spark,akopich/spark,janewangfb/spark,byakuinss/spark,aokolnychyi/spark,Aegeaner/spark,nchammas/spark,jrshust/spark,hvanhovell/spark,tejasapatil/spark,michalsenkyr/spark,apache/spark,JerryLead/spark,andrewor14/iolap,vax11780/spark,andrewor14/iolap,tejasapatil/spark,rikima/spark,gioenn/xSpark,srowen/spark,mkolod/incubator-spark,bdrillard/spark,WeichenXu123/spark,cloudera/spark,MLnick/spark,wgpshashank/spark,rezasafi/spark,Aegeaner/spark,aray/spark,highfei2011/spark,spark-test/spark,brad-kaiser/spark,lxsmnv/spark,ioana-delaney/spark,zero323/spark,someorz/spark,setjet/spark,ConeyLiu/spark,lxsmnv/spark,ioana-delaney/spark,koeninger/spark,JoshRosen/spark,joseph-torres/spark,huang1900/spark,minixalpha/spark,rikima/spark,pgandhi999/spark,highfei2011/spark,BryanCutler/spark,liyichao/spark,ioana-delaney/spark,debugger87/spark,srowen/spark,aray/spark,skonto/spark,ConeyLiu/spark,loneknightpy/spark,ibm-research-ireland/sparkoscope,SHASHANKB/spark,haowu80s/spark,mahak/spark,guoxiaolongzte/spark,tengpeng/spark,big-pegasus/spark,shubhamchopra/spark,byakuinss/spark,vax11780/spark,joseph-torres/spark,sureshthalamati/spark,kevinyu98/spark,huang1900/spark,icexelloss/spark,kissmetrics/spark,big-pegasus/spark,ajaysaini725/spark,aokolnychyi/spark,vinodkc/spark,debugger87/spark,bOOm-X/spark,hvanhovell/spark,SnappyDataInc/spark,matthewfranglen/spark,JerryLead/spark,patrick-nicholson/spark,ptkool/spark,joseph-torres/spark,aosagie/spark,big-pegasus/spark,kevinyu98/spark,ueshin/apache-spark,jkbradley/spark,mkolod/incubator-spark,esi-mineset/spark,narahari92/spark,aray/spark,dongjoon-hyun/spark,rekhajoshm/spark,taroplus/spark,maropu/spark,map222/spark,ueshin/apache-spark,ConeyLiu/spark,chuckchen/spark,gengliangwang/spark,michalsenkyr/spark,vinodkc/spark,taroplus/spark,szhem/spark,wzhfy/spark,goldmedal/spark,techaddict/spark,maropu/spark,guoxiaolongzte/spark,bdrillard/spark,spark-test/spark,facaiy/spark,bravo-zhang/spark,aokolnychyi/spark,bdrillard/spark,bravo-zhang/spark,actuaryzhang/spark,bOOm-X/spark,esi-mineset/spark,xuanyuanking/spark,poffuomo/spark,jkbradley/spark,brad-kaiser/spark,hvanhovell/spark,mike0sv/spark,aosagie/spark,someorz/spark,facaiy/spark,highfei2011/spark,skonto/spark,srowen/spark,ueshin/apache-spark,kissmetrics/spark,mike0sv/spark,MLnick/spark,rezasafi/spark,facaiy/spark,lvdongr/spark,eyalfa/spark,zhouyejoe/spark,minixalpha/spark,big-pegasus/spark,jrshust/spark,xflin/spark,metamx/spark,liutang123/spark,Panos-Bletsos/spark-cost-model-optimizer,facaiy/spark,ericvandenbergfb/spark,akopich/spark,ron8hu/spark,bdrillard/spark,srowen/spark,jianran/spark,mzl9039/spark,wgpshashank/spark,ddna1021/spark,gengliangwang/spark,ibm-research-ireland/sparkoscope,aray/spark,yanboliang/spark,andrewor14/spark,liutang123/spark,poffuomo/spark,ptkool/spark,shuangshuangwang/spark,lxsmnv/spark,markhamstra/spark