cmd/go: build errors rather than strings in some tests
cmd/go: build errors rather than strings in some tests

Speed up the test suite by building the errors package rather than the
strings package in some cases where the specific package we are
building doesn't matter.  The errors package is smaller, and doesn't
have any assembler code.

Also make a couple of tests run in parallel.

Update #11779.

Change-Id: I62e47f8655f9d85bf93c70ae6e6121276d96aee0
Reviewed-on: https://go-review.googlesource.com/12365
Run-TryBot: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
Reviewed-by: David Crawshaw <a2f0bf29257797dd66800b4fbb9945c3e216c004@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

famorted/go,monetate/go,akutz/go,vsdutka/go,cnbin/go,zhangg/go,springning/go,chinanjjohn2012/go,mgyenik/go,myPublicGit/go,g522342435/go,sosop/go,RBEGamer/go,jonathanmarvens/go,roth1002/go,springning/go,uileyar/go,malvira/go,Stan-Lin-/go,Cofyc/go,mgyenik/go,dkolbly/go,ichu501/go,Stan-Lin-/go,donnel6809/go,constantine001/go,snowsnail/go,willjunspecial/go,cookerzhu/go,Cofyc/go,danielsoro/go,uileyar/go,vanloswang/go,cloudflare/go,willjunspecial/go,beealone/go,cloudflare/go,cnbin/go,Young55555/go,Young55555/go,stormltf/go,jameskumar/go,pgmreddy/go,willjunspecial/go,jacobxk/go,Charlesdong/go-1,dterei/go,joshsammut/go,Samurais/go,jacobsa/go,qskycolor/go,CAFxX/go,WIZARD-CXY/go,Jordanzuo/go,danycoro/go,willjunspecial/go,youprofit/go,mgyenik/go,ImJasonH/go,alex-zhang/go,wangfakang/go-1,xiaobodu/go,gdey/go,xiaobodu/go,roth1002/go,ObjectiveJoe/go,springning/go,Samurais/go,jacobxk/go,vsekhar/elastic-go,ErikDubbelboer/go,miolini/go,momchil-velikov/go,beealone/go,cloudrain21/go,momchil-velikov/go,roth1002/go,cainiaocome/go,zcwfeng/go,vsekhar/elastic-go,cnbin/go,b54898533/go,jdeng/go,xiuzhifu/go,binarycrusader/go,Jordanzuo/go,dafyddcrosby/go,polyverse-security/go,yangzhongj/go,andrewchambers/go,RBEGamer/go,arschles/golang-go,mbrukman/go,goodlang/good,jmptrader/go,snowsnail/go,dpatel06/go,polyverse-security/go,Young55555/go,kevinc0825/go,jmptrader/go,RBEGamer/go,akutz/go,Charlesdong/go-1,gohin/go,stormltf/go,youprofit/go,xujianhai/go,greyhwndz/go,polyverse-security/go,parkdy/go,g522342435/go,gohin/go,jmptrader/go,jefby/go,derekmarcotte/go,XuYunnan/go,constantine001/go,ObjectiveJoe/go,jdhenke/go,ifagnosticism/go,xujianhai/go,leeric92/go,lihuanghai/go,ericsnowcurrently/go,RBEGamer/go,alex-zhang/go,jdeng/go,snowsnail/go,gohin/go,ifagnosticism/go,cloudflare/go,NichoZhang/go,stormltf/go,xujianhai/go,arschles/go-1,honsiorovskyi/go,CodyGuo/go,goodlang/good,undergrowthlinear/go,cainiaocome/go,ImJasonH/go,yasarkunduz/go,Stan-Lin-/go,greyhwndz/go,CodyGuo/go,ichu501/go,Badredapple/go,theass/go,ericsnowcurrently/go,honsiorovskyi/go,rachtsingh/gogojuice,g522342435/go,suncycheng/go,kakuhiroshi/go,CarterTsai/go,ichu501/go,willjunspecial/go,jacobhaven/go,pgmreddy/go,kim-racktop/go,vishsingh/go,snowsnail/go,greyhwndz/go,GeorgiCodes/go,JioCloud/go,linux-on-ibm-z/go,ericsnowcurrently/go,theass/go,jdhenke/go,dterei/go,jacobsa/go,nakedgc/go,Pulgafree/go,monetate/go,kim-racktop/go,Samurais/go,NunoEdgarGub1/go,deft-code/go,polyverse-security/go,yuhengye/go,jefby/go,mikekap/go,CodyGuo/go,vanloswang/go,CiscoCloud/go,Samurais/go,beealone/go,dpatel06/go,kevinc0825/go,danycoro/go,CiscoCloud/go,ifagnosticism/go,andrewchambers/go,wangfakang/go-1,4ad/go,sndnvaps/go,derekmarcotte/go,rentongzhang/go,deft-code/go,dkolbly/go,b54898533/go,dkolbly/go,cloudrain21/go,NichoZhang/go,roth1002/go,Stan-Lin-/go,ErikDubbelboer/go,ErikDubbelboer/go,uileyar/go,mdp/go,jameskumar/go,Samurais/go,sosop/go,cloudrain21/go,yasarkunduz/go,cookerzhu/go,jefby/go,vsekhar/elastic-go,danycoro/go,ifagnosticism/go,cookerzhu/go,roth1002/go,gohin/go,jasonxiong/go,ErikDubbelboer/go,fjballest/golang,momchil-velikov/go,vishsingh/go,kim-racktop/go,kim-racktop/go,Cofyc/go,jonathanmarvens/go,kakuhiroshi/go,shines77/go,Charlesdong/go-1,likesea/go,arschles/go-1,mbrukman/go,xujianhai/go,theif519/go,myPublicGit/go,NunoEdgarGub1/go,dkolbly/go,pgmreddy/go,b54898533/go,jacobsa/go,dterei/go,fjballest/golang,yuhengye/go,ObjectiveJoe/go,Pulgafree/go,Pulgafree/go,Endika/go,baiyunping333/go,polyverse-security/go,AALEKH/go,joshsammut/go,odeke-em/go,leeric92/go,baiyunping333/go,likesea/go,mikekap/go,jameskumar/go,miolini/go,miolini/go,jonahglover/go,nawawi/go,sosop/go,jameskumar/go,lihuanghai/go,dgnorton/go,NunoEdgarGub1/go,GeorgiCodes/go,greyhwndz/go,monetate/go,devpadawan/go,NichoZhang/go,dterei/go,Charlesdong/go-1,ObjectiveJoe/go,lihuanghai/go,rachtsingh/gogojuice,ifagnosticism/go,jonasi/go,arschles/golang-go,kevinc0825/go,christopher-henderson/Go,g522342435/go,willjunspecial/go,greyhwndz/go,mgyenik/go,chinanjjohn2012/go,JioCloud/go,slavau/go,parkdy/go,mikekap/go,snowsnail/go,CodyGuo/go,jmptrader/go,jacobhaven/go,Endika/go,skatsuta/go,danielsoro/go,baiyunping333/go,jasonxiong/go,jasonxiong/go,Samurais/go,rentongzhang/go,alash3al/go,dafyddcrosby/go,arschles/go-1,b54898533/go,parkdy/go,ObjectiveJoe/go,rachtsingh/gogojuice,kim-racktop/go,skotti/go,golang/go,nawawi/go,WIZARD-CXY/go,codestation/go,donnel6809/go,nakedgc/go,theass/go,cloudrain21/go,xinhuang327/go,sndnvaps/go,stormltf/go,danycoro/go,alash3al/go,ganboing/go-esx,lihuanghai/go,goodlang/good,deft-code/go,cyberroadie/go,rentongzhang/go,andrewchambers/go,ganboing/go-esx,CAFxX/go,jacobsa/go,vishsingh/go,mbrukman/go,XuYunnan/go,NichoZhang/go,constantine001/go,devpadawan/go,constantine001/go,jdeng/go,mwhudson/go,derekmarcotte/go,beealone/go,donnel6809/go,XuYunnan/go,kakuhiroshi/go,donnel6809/go,gdey/go,roth1002/go,jacobhaven/go,rachtsingh/gogojuice,undergrowthlinear/go,alash3al/go,XuYunnan/go,codestation/go,jdeng/go,ifagnosticism/go,fjballest/golang,vanloswang/go,alex-zhang/go,shazow/go,akutz/go,momchil-velikov/go,samanalysis/go,donnel6809/go,mgyenik/go,CiscoCloud/go,ericsnowcurrently/go,Jordanzuo/go,vishsingh/go,Badredapple/go,shazow/go,rentongzhang/go,arschles/go-1,4ad/go,shines77/go,uileyar/go,binarycrusader/go,zouchao2010/go,dpatel06/go,likesea/go,Cofyc/go,albertjin/golang-go,CAFxX/go,Endika/go,xinhuang327/go,skatsuta/go,jameskumar/go,CarterTsai/go,vsekhar/elastic-go,kevinc0825/go,ichu501/go,akutz/go,NichoZhang/go,zcwfeng/go,cyberroadie/go,josharian/go,Endika/go,jacobhaven/go,slavau/go,cookerzhu/go,derekmarcotte/go,mdp/go,g522342435/go,odeke-em/go,rachtsingh/gogojuice,undergrowthlinear/go,skotti/go,dterei/go,xiuzhifu/go,zhangg/go,JioCloud/go,ObjectiveJoe/go,Stan-Lin-/go,chinanjjohn2012/go,constantine001/go,josharian/go,albertjin/golang-go,dpatel06/go,donnel6809/go,ImJasonH/go,AALEKH/go,GeorgiCodes/go,yangzhongj/go,RBEGamer/go,samanalysis/go,CiscoCloud/go,g522342435/go,shazow/go,springning/go,skatsuta/go,AALEKH/go,lihuanghai/go,arschles/golang-go,zhangg/go,vsdutka/go,AALEKH/go,ifagnosticism/go,leeric92/go,slavau/go,dterei/go,gohin/go,youprofit/go,Charlesdong/go-1,NichoZhang/go,CarterTsai/go,jacobxk/go,greyhwndz/go,jonahglover/go,dafyddcrosby/go,youprofit/go,baiyunping333/go,leeric92/go,slavau/go,jefby/go,cookerzhu/go,pgmreddy/go,sndnvaps/go,suncycheng/go,skotti/go,mdp/go,alash3al/go,devpadawan/go,wangfakang/go-1,cloudrain21/go,linux-on-ibm-z/go,Jordanzuo/go,Badredapple/go,jacobhaven/go,cnbin/go,jasonxiong/go,likesea/go,mwhudson/go,myPublicGit/go,theass/go,jdhenke/go,yuhengye/go,cainiaocome/go,sndnvaps/go,xujianhai/go,jasonxiong/go,pgmreddy/go,gohin/go,yuhengye/go,undergrowthlinear/go,fjballest/golang,Young55555/go,jacobhaven/go,ImJasonH/go,akutz/go,linux-on-ibm-z/go,deft-code/go,xiaobodu/go,vanloswang/go,Pulgafree/go,WIZARD-CXY/go,alash3al/go,constantine001/go,suncycheng/go,donnel6809/go,ImJasonH/go,JioCloud/go,jdhenke/go,kim-racktop/go,odeke-em/go,xujianhai/go,dgnorton/go,dterei/go,joshsammut/go,zhangg/go,linux-on-ibm-z/go,baiyunping333/go,CAFxX/go,danycoro/go,Cofyc/go,xinhuang327/go,ErikDubbelboer/go,Cofyc/go,beealone/go,Pulgafree/go,rentongzhang/go,danielsoro/go,suncycheng/go,parkdy/go,monetate/go,Charlesdong/go-1,sinuos/go,mdp/go,zhangg/go,shazow/go,kakuhiroshi/go,kevinc0825/go,ericsnowcurrently/go,uileyar/go,samanalysis/go,wangfakang/go-1,josharian/go,nakedgc/go,xiaobodu/go,jasonxiong/go,constantine001/go,malvira/go,goodlang/good,shines77/go,cloudrain21/go,cyberroadie/go,polyverse-security/go,cloudflare/go,zouchao2010/go,albertjin/golang-go,donnel6809/go,joshsammut/go,alex-zhang/go,myPublicGit/go,jasonxiong/go,rachtsingh/gogojuice,AALEKH/go,greyhwndz/go,fjballest/golang,mdp/go,CodyGuo/go,honsiorovskyi/go,arschles/go-1,vsdutka/go,deft-code/go,nawawi/go,CiscoCloud/go,gdey/go,binarycrusader/go,yasarkunduz/go,mdp/go,dgnorton/go,golang/go,josharian/go,kakuhiroshi/go,kim-racktop/go,g522342435/go,sinuos/go,CodyGuo/go,qskycolor/go,yuhengye/go,cloudrain21/go,codestation/go,dafyddcrosby/go,lihuanghai/go,goodlang/good,sosop/go,ImJasonH/go,albertjin/golang-go,vsdutka/go,cainiaocome/go,zouchao2010/go,vishsingh/go,derekmarcotte/go,beealone/go,gdey/go,jonathanmarvens/go,ganboing/go-esx,shines77/go,jacobxk/go,skotti/go,josharian/go,WIZARD-CXY/go,b54898533/go,linux-on-ibm-z/go,myPublicGit/go,ganboing/go-esx,nakedgc/go,XuYunnan/go,yangzhongj/go,undergrowthlinear/go,akutz/go,jacobxk/go,Stan-Lin-/go,Charlesdong/go-1,malvira/go,Badredapple/go,miolini/go,monetate/go,ganboing/go-esx,WIZARD-CXY/go,mbrukman/go,XuYunnan/go,CAFxX/go,NunoEdgarGub1/go,youprofit/go,Stan-Lin-/go,monetate/go,gdey/go,Young55555/go,yuhengye/go,jacobxk/go,golang/go,xiaobodu/go,arschles/golang-go,vishsingh/go,youprofit/go,wangfakang/go-1,theass/go,sosop/go,goodlang/good,binarycrusader/go,leeric92/go,cainiaocome/go,cookerzhu/go,jonahglover/go,cloudflare/go,zouchao2010/go,Endika/go,jacobsa/go,kim-racktop/go,odeke-em/go,youprofit/go,honsiorovskyi/go,yangzhongj/go,wangfakang/go-1,dafyddcrosby/go,binarycrusader/go,danielsoro/go,uileyar/go,WIZARD-CXY/go,4ad/go,samanalysis/go,polyverse-security/go,springning/go,joshsammut/go,4ad/go,zouchao2010/go,shines77/go,Endika/go,qskycolor/go,pgmreddy/go,jacobxk/go,cloudflare/go,skotti/go,yangzhongj/go,zcwfeng/go,dgnorton/go,golang/go,deft-code/go,fjballest/golang,samanalysis/go,golang/go,xiuzhifu/go,cainiaocome/go,JioCloud/go,theif519/go,xujianhai/go,codestation/go,alex-zhang/go,suncycheng/go,danielsoro/go,g522342435/go,xiaobodu/go,baiyunping333/go,alex-zhang/go,odeke-em/go,arschles/golang-go,odeke-em/go,kakuhiroshi/go,dafyddcrosby/go,binarycrusader/go,Charlesdong/go-1,kakuhiroshi/go,jdeng/go,jonasi/go,malvira/go,snowsnail/go,stormltf/go,mbrukman/go,jonahglover/go,devpadawan/go,sinuos/go,vanloswang/go,dgnorton/go,danycoro/go,codestation/go,Samurais/go,danielsoro/go,stormltf/go,alash3al/go,shines77/go,b54898533/go,dterei/go,mwhudson/go,gdey/go,kevinc0825/go,GeorgiCodes/go,danielsoro/go,golang/go,dafyddcrosby/go,famorted/go,honsiorovskyi/go,albertjin/golang-go,sndnvaps/go,zcwfeng/go,CiscoCloud/go,snowsnail/go,yasarkunduz/go,andrewchambers/go,beealone/go,Stan-Lin-/go,myPublicGit/go,gdey/go,josharian/go,ericsnowcurrently/go,akutz/go,Endika/go,samanalysis/go,Young55555/go,alex-zhang/go,joshsammut/go,Pulgafree/go,AALEKH/go,leeric92/go,nakedgc/go,RBEGamer/go,GeorgiCodes/go,linux-on-ibm-z/go,xiuzhifu/go,skotti/go,jonathanmarvens/go,ganboing/go-esx,jdhenke/go,zouchao2010/go,Cofyc/go,sndnvaps/go,chinanjjohn2012/go,jacobsa/go,zcwfeng/go,uileyar/go,cnbin/go,yangzhongj/go,Endika/go,momchil-velikov/go,theass/go,yasarkunduz/go,xinhuang327/go,samanalysis/go,jonahglover/go,willjunspecial/go,suncycheng/go,xinhuang327/go,dpatel06/go,rachtsingh/gogojuice,theif519/go,honsiorovskyi/go,ichu501/go,arschles/go-1,andrewchambers/go,sinuos/go,vsekhar/elastic-go,deft-code/go,XuYunnan/go,xiuzhifu/go,zhangg/go,jameskumar/go,Jordanzuo/go,vanloswang/go,likesea/go,sinuos/go,jasonxiong/go,monetate/go,famorted/go,theass/go,greyhwndz/go,mdp/go,vanloswang/go,xiuzhifu/go,WIZARD-CXY/go,cookerzhu/go,arschles/golang-go,skatsuta/go,CodyGuo/go,jmptrader/go,momchil-velikov/go,mwhudson/go,jonasi/go,ganboing/go-esx,ericsnowcurrently/go,miolini/go,jonasi/go,xiuzhifu/go,andrewchambers/go,jdhenke/go,sosop/go,CarterTsai/go,baiyunping333/go,springning/go,vsekhar/elastic-go,sinuos/go,GeorgiCodes/go,roth1002/go,jacobsa/go,malvira/go,kakuhiroshi/go,NichoZhang/go,rentongzhang/go,joshsammut/go,likesea/go,wangfakang/go-1,rachtsingh/gogojuice,jonathanmarvens/go,goodlang/good,xiuzhifu/go,mwhudson/go,theass/go,devpadawan/go,qskycolor/go,jacobsa/go,xiaobodu/go,binarycrusader/go,sinuos/go,Badredapple/go,myPublicGit/go,CiscoCloud/go,vsekhar/elastic-go,zcwfeng/go,dafyddcrosby/go,sndnvaps/go,jdhenke/go,jonasi/go,slavau/go,ichu501/go,cnbin/go,arschles/go-1,4ad/go,skatsuta/go,cyberroadie/go,honsiorovskyi/go,CAFxX/go,cnbin/go,Badredapple/go,polyverse-security/go,devpadawan/go,yasarkunduz/go,chinanjjohn2012/go,famorted/go,jonahglover/go,springning/go,golang/go,mbrukman/go,slavau/go,deft-code/go,vishsingh/go,snowsnail/go,famorted/go,albertjin/golang-go,stormltf/go,zouchao2010/go,baiyunping333/go,roth1002/go,cookerzhu/go,dpatel06/go,zhangg/go,nawawi/go,jdeng/go,undergrowthlinear/go,linux-on-ibm-z/go,b54898533/go,ErikDubbelboer/go,jacobxk/go,theif519/go,dkolbly/go,shazow/go,derekmarcotte/go,jonathanmarvens/go,Jordanzuo/go,momchil-velikov/go,sndnvaps/go,yangzhongj/go,kevinc0825/go,jefby/go,Jordanzuo/go,ericsnowcurrently/go,myPublicGit/go,dkolbly/go,odeke-em/go,devpadawan/go,codestation/go,derekmarcotte/go,sosop/go,gdey/go,famorted/go,WIZARD-CXY/go,slavau/go,CiscoCloud/go,dpatel06/go,jmptrader/go,qskycolor/go,albertjin/golang-go,ObjectiveJoe/go,NichoZhang/go,mikekap/go,golang/go,xinhuang327/go,miolini/go,josharian/go,dkolbly/go,GeorgiCodes/go,skatsuta/go,vsdutka/go,sinuos/go,skatsuta/go,andrewchambers/go,ichu501/go,NunoEdgarGub1/go,CarterTsai/go,GeorgiCodes/go,kevinc0825/go,Jordanzuo/go,mwhudson/go,likesea/go,arschles/go-1,dgnorton/go,jonahglover/go,RBEGamer/go,CAFxX/go,Badredapple/go,chinanjjohn2012/go,mikekap/go,AALEKH/go,nawawi/go,jacobhaven/go,mbrukman/go,cyberroadie/go,derekmarcotte/go,nakedgc/go,JioCloud/go,CarterTsai/go,linux-on-ibm-z/go,nawawi/go,willjunspecial/go,uileyar/go,JioCloud/go,wangfakang/go-1,mwhudson/go,CarterTsai/go,vsekhar/elastic-go,cnbin/go,RBEGamer/go,Samurais/go,jmptrader/go,shazow/go,constantine001/go,zcwfeng/go,b54898533/go,youprofit/go,beealone/go,yuhengye/go,rentongzhang/go,suncycheng/go,albertjin/golang-go,mikekap/go,ifagnosticism/go,codestation/go,theif519/go,nawawi/go,jmptrader/go,pgmreddy/go,yuhengye/go,shazow/go,4ad/go,nawawi/go,parkdy/go,CAFxX/go,rentongzhang/go,Pulgafree/go,Young55555/go,dpatel06/go,cainiaocome/go,parkdy/go,yangzhongj/go,yasarkunduz/go,qskycolor/go,mgyenik/go,arschles/golang-go,ErikDubbelboer/go,mgyenik/go,jdeng/go,famorted/go,akutz/go,dgnorton/go,zhangg/go,skotti/go,famorted/go,jefby/go,cainiaocome/go,gohin/go,momchil-velikov/go,leeric92/go,Badredapple/go,CarterTsai/go,jacobhaven/go,chinanjjohn2012/go,nakedgc/go,zcwfeng/go,monetate/go,Pulgafree/go,binarycrusader/go,mwhudson/go,vsdutka/go,theif519/go,xiaobodu/go,malvira/go,mgyenik/go,devpadawan/go,jameskumar/go,mikekap/go,CodyGuo/go,chinanjjohn2012/go,dgnorton/go,honsiorovskyi/go,jonathanmarvens/go,malvira/go,theif519/go,nakedgc/go,suncycheng/go,JioCloud/go,qskycolor/go,gohin/go,jonathanmarvens/go,pgmreddy/go,qskycolor/go,joshsammut/go,xinhuang327/go,4ad/go,samanalysis/go,NunoEdgarGub1/go,shines77/go,ichu501/go,malvira/go,undergrowthlinear/go,cyberroadie/go,codestation/go,goodlang/good,arschles/golang-go,danycoro/go,ImJasonH/go,jonahglover/go,jefby/go,jameskumar/go,fjballest/golang,cyberroadie/go,zouchao2010/go,danielsoro/go,vanloswang/go,undergrowthlinear/go,ganboing/go-esx,xinhuang327/go,leeric92/go,jonasi/go,xujianhai/go,cloudrain21/go,XuYunnan/go,mikekap/go,skotti/go,ImJasonH/go,parkdy/go,lihuanghai/go,vishsingh/go,parkdy/go,shazow/go,shines77/go,cloudflare/go,4ad/go,cloudflare/go,vsdutka/go,ErikDubbelboer/go,NunoEdgarGub1/go,danycoro/go,Young55555/go,miolini/go,dkolbly/go,jdhenke/go,likesea/go,NunoEdgarGub1/go,jonasi/go,jdeng/go,vsdutka/go,jefby/go,slavau/go,mdp/go,sosop/go,skatsuta/go,Cofyc/go,jonasi/go,alash3al/go,mbrukman/go,alash3al/go,AALEKH/go,josharian/go,ObjectiveJoe/go,stormltf/go,miolini/go,springning/go,yasarkunduz/go,cyberroadie/go,lihuanghai/go,odeke-em/go,alex-zhang/go,fjballest/golang,theif519/go,andrewchambers/go