Update Developer-Guide.md
Update Developer-Guide.md

Add note about passing testing parameters to xunit.

nbarbettini/corefx,shahid-pk/corefx,viniciustaveira/corefx,seanshpark/corefx,comdiv/corefx,khdang/corefx,nchikanov/corefx,lydonchandra/corefx,Alcaro/corefx,ericstj/corefx,shmao/corefx,DnlHarvey/corefx,benjamin-bader/corefx,rajansingh10/corefx,rahku/corefx,pgavlin/corefx,vidhya-bv/corefx-sorting,rahku/corefx,Frank125/corefx,anjumrizwi/corefx,jcme/corefx,kyulee1/corefx,richlander/corefx,dotnet-bot/corefx,alphonsekurian/corefx,erpframework/corefx,spoiledsport/corefx,zhenlan/corefx,brett25/corefx,DnlHarvey/corefx,claudelee/corefx,alexandrnikitin/corefx,alphonsekurian/corefx,yizhang82/corefx,mmitche/corefx,axelheer/corefx,shiftkey-tester/corefx,ravimeda/corefx,Winsto/corefx,MaggieTsang/corefx,janhenke/corefx,stormleoxia/corefx,PatrickMcDonald/corefx,shimingsg/corefx,Yanjing123/corefx,dhoehna/corefx,yizhang82/corefx,khdang/corefx,Chrisboh/corefx,fgreinacher/corefx,vidhya-bv/corefx-sorting,marksmeltzer/corefx,matthubin/corefx,janhenke/corefx,mazong1123/corefx,fgreinacher/corefx,gregg-miskelly/corefx,KrisLee/corefx,janhenke/corefx,akivafr123/corefx,seanshpark/corefx,shiftkey-tester/corefx,Ermiar/corefx,JosephTremoulet/corefx,MaggieTsang/corefx,matthubin/corefx,zmaruo/corefx,nelsonsar/corefx,larsbj1988/corefx,Priya91/corefx-1,ravimeda/corefx,ellismg/corefx,mazong1123/corefx,mazong1123/corefx,cydhaselton/corefx,ravimeda/corefx,ViktorHofer/corefx,xuweixuwei/corefx,dhoehna/corefx,akivafr123/corefx,zhenlan/corefx,s0ne0me/corefx,weltkante/corefx,jcme/corefx,nbarbettini/corefx,erpframework/corefx,CloudLens/corefx,yizhang82/corefx,dotnet-bot/corefx,vs-team/corefx,bitcrazed/corefx,yizhang82/corefx,Chrisboh/corefx,tijoytom/corefx,gkhanna79/corefx,Ermiar/corefx,shahid-pk/corefx,uhaciogullari/corefx,pallavit/corefx,jcme/corefx,SGuyGe/corefx,MaggieTsang/corefx,shana/corefx,JosephTremoulet/corefx,akivafr123/corefx,jlin177/corefx,mellinoe/corefx,rahku/corefx,uhaciogullari/corefx,josguil/corefx,Alcaro/corefx,cnbin/corefx,CherryCxldn/corefx,mokchhya/corefx,mmitche/corefx,viniciustaveira/corefx,690486439/corefx,shimingsg/corefx,ptoonen/corefx,stone-li/corefx,ravimeda/corefx,BrennanConroy/corefx,zmaruo/corefx,vrassouli/corefx,CherryCxldn/corefx,kyulee1/corefx,krk/corefx,zhangwenquan/corefx,twsouthwick/corefx,MaggieTsang/corefx,chenkennt/corefx,erpframework/corefx,khdang/corefx,mokchhya/corefx,690486439/corefx,pgavlin/corefx,chenkennt/corefx,lydonchandra/corefx,rjxby/corefx,rubo/corefx,heXelium/corefx,chenxizhang/corefx,mokchhya/corefx,Jiayili1/corefx,andyhebear/corefx,vidhya-bv/corefx-sorting,twsouthwick/corefx,jlin177/corefx,viniciustaveira/corefx,gabrielPeart/corefx,ellismg/corefx,EverlessDrop41/corefx,misterzik/corefx,Petermarcu/corefx,anjumrizwi/corefx,mmitche/corefx,xuweixuwei/corefx,nbarbettini/corefx,gregg-miskelly/corefx,Petermarcu/corefx,elijah6/corefx,KrisLee/corefx,cartermp/corefx,mokchhya/corefx,oceanho/corefx,benjamin-bader/corefx,andyhebear/corefx,shahid-pk/corefx,CloudLens/corefx,scott156/corefx,benpye/corefx,nbarbettini/corefx,cnbin/corefx,shimingsg/corefx,PatrickMcDonald/corefx,jcme/corefx,wtgodbe/corefx,kkurni/corefx,parjong/corefx,stormleoxia/corefx,zhenlan/corefx,alphonsekurian/corefx,tijoytom/corefx,SGuyGe/corefx,nelsonsar/corefx,Frank125/corefx,tstringer/corefx,mellinoe/corefx,mellinoe/corefx,krk/corefx,elijah6/corefx,dtrebbien/corefx,huanjie/corefx,the-dwyer/corefx,jhendrixMSFT/corefx,heXelium/corefx,mmitche/corefx,Jiayili1/corefx,SGuyGe/corefx,jlin177/corefx,stone-li/corefx,shrutigarg/corefx,wtgodbe/corefx,weltkante/corefx,manu-silicon/corefx,cartermp/corefx,cartermp/corefx,kyulee1/corefx,twsouthwick/corefx,billwert/corefx,iamjasonp/corefx,ptoonen/corefx,alexperovich/corefx,oceanho/corefx,dtrebbien/corefx,tstringer/corefx,lggomez/corefx,dotnet-bot/corefx,zhenlan/corefx,stephenmichaelf/corefx,shmao/corefx,alphonsekurian/corefx,elijah6/corefx,yizhang82/corefx,SGuyGe/corefx,tstringer/corefx,bpschoch/corefx,dtrebbien/corefx,cydhaselton/corefx,kkurni/corefx,richlander/corefx,shiftkey-tester/corefx,pgavlin/corefx,zhenlan/corefx,heXelium/corefx,bpschoch/corefx,vs-team/corefx,rajansingh10/corefx,nelsonsar/corefx,billwert/corefx,YoupHulsebos/corefx,rjxby/corefx,CherryCxldn/corefx,jeremymeng/corefx,shana/corefx,ViktorHofer/corefx,adamralph/corefx,billwert/corefx,dhoehna/corefx,chenxizhang/corefx,tijoytom/corefx,iamjasonp/corefx,jlin177/corefx,jmhardison/corefx,CherryCxldn/corefx,marksmeltzer/corefx,huanjie/corefx,KrisLee/corefx,Jiayili1/corefx,rahku/corefx,mellinoe/corefx,oceanho/corefx,Ermiar/corefx,n1ghtmare/corefx,richlander/corefx,billwert/corefx,misterzik/corefx,shahid-pk/corefx,Jiayili1/corefx,ptoonen/corefx,vrassouli/corefx,fgreinacher/corefx,jhendrixMSFT/corefx,nchikanov/corefx,scott156/corefx,elijah6/corefx,parjong/corefx,kyulee1/corefx,alphonsekurian/corefx,tstringer/corefx,Yanjing123/corefx,vrassouli/corefx,benpye/corefx,wtgodbe/corefx,richlander/corefx,yizhang82/corefx,shmao/corefx,n1ghtmare/corefx,comdiv/corefx,wtgodbe/corefx,Priya91/corefx-1,dotnet-bot/corefx,SGuyGe/corefx,bitcrazed/corefx,Frank125/corefx,Alcaro/corefx,dhoehna/corefx,pallavit/corefx,s0ne0me/corefx,marksmeltzer/corefx,cartermp/corefx,nchikanov/corefx,cartermp/corefx,lydonchandra/corefx,DnlHarvey/corefx,zhenlan/corefx,stephenmichaelf/corefx,kkurni/corefx,mellinoe/corefx,jhendrixMSFT/corefx,akivafr123/corefx,alexandrnikitin/corefx,the-dwyer/corefx,cydhaselton/corefx,krytarowski/corefx,wtgodbe/corefx,stone-li/corefx,alexperovich/corefx,chaitrakeshav/corefx,s0ne0me/corefx,dkorolev/corefx,YoupHulsebos/corefx,bpschoch/corefx,the-dwyer/corefx,Winsto/corefx,Petermarcu/corefx,KrisLee/corefx,thiagodin/corefx,fernando-rodriguez/corefx,ViktorHofer/corefx,Petermarcu/corefx,CloudLens/corefx,YoupHulsebos/corefx,tijoytom/corefx,stephenmichaelf/corefx,misterzik/corefx,matthubin/corefx,krytarowski/corefx,DnlHarvey/corefx,gabrielPeart/corefx,jhendrixMSFT/corefx,PatrickMcDonald/corefx,manu-silicon/corefx,gregg-miskelly/corefx,nchikanov/corefx,twsouthwick/corefx,shimingsg/corefx,YoupHulsebos/corefx,Jiayili1/corefx,ericstj/corefx,s0ne0me/corefx,axelheer/corefx,ViktorHofer/corefx,destinyclown/corefx,claudelee/corefx,dkorolev/corefx,Ermiar/corefx,axelheer/corefx,krytarowski/corefx,gkhanna79/corefx,JosephTremoulet/corefx,larsbj1988/corefx,seanshpark/corefx,EverlessDrop41/corefx,anjumrizwi/corefx,tijoytom/corefx,iamjasonp/corefx,kkurni/corefx,larsbj1988/corefx,iamjasonp/corefx,bitcrazed/corefx,krytarowski/corefx,shmao/corefx,690486439/corefx,Jiayili1/corefx,jmhardison/corefx,jcme/corefx,cydhaselton/corefx,vijaykota/corefx,JosephTremoulet/corefx,kkurni/corefx,adamralph/corefx,shimingsg/corefx,jhendrixMSFT/corefx,jmhardison/corefx,kkurni/corefx,benpye/corefx,mokchhya/corefx,jhendrixMSFT/corefx,SGuyGe/corefx,dotnet-bot/corefx,khdang/corefx,gabrielPeart/corefx,Ermiar/corefx,shahid-pk/corefx,brett25/corefx,akivafr123/corefx,richlander/corefx,lggomez/corefx,benpye/corefx,claudelee/corefx,andyhebear/corefx,YoupHulsebos/corefx,nchikanov/corefx,stone-li/corefx,jcme/corefx,nbarbettini/corefx,gkhanna79/corefx,MaggieTsang/corefx,chaitrakeshav/corefx,dkorolev/corefx,jeremymeng/corefx,elijah6/corefx,CloudLens/corefx,adamralph/corefx,huanjie/corefx,billwert/corefx,EverlessDrop41/corefx,seanshpark/corefx,pallavit/corefx,josguil/corefx,manu-silicon/corefx,twsouthwick/corefx,stephenmichaelf/corefx,mazong1123/corefx,mazong1123/corefx,vidhya-bv/corefx-sorting,stephenmichaelf/corefx,fernando-rodriguez/corefx,gregg-miskelly/corefx,DnlHarvey/corefx,huanjie/corefx,Petermarcu/corefx,Alcaro/corefx,the-dwyer/corefx,shmao/corefx,brett25/corefx,cnbin/corefx,twsouthwick/corefx,elijah6/corefx,ViktorHofer/corefx,alphonsekurian/corefx,Yanjing123/corefx,yizhang82/corefx,tstringer/corefx,jmhardison/corefx,benpye/corefx,jhendrixMSFT/corefx,khdang/corefx,cydhaselton/corefx,mokchhya/corefx,ViktorHofer/corefx,tstringer/corefx,rajansingh10/corefx,stormleoxia/corefx,krytarowski/corefx,rubo/corefx,Yanjing123/corefx,cartermp/corefx,dhoehna/corefx,the-dwyer/corefx,marksmeltzer/corefx,ptoonen/corefx,Priya91/corefx-1,benjamin-bader/corefx,axelheer/corefx,shiftkey-tester/corefx,jlin177/corefx,gkhanna79/corefx,spoiledsport/corefx,janhenke/corefx,billwert/corefx,lggomez/corefx,VPashkov/corefx,alexperovich/corefx,shahid-pk/corefx,josguil/corefx,weltkante/corefx,lggomez/corefx,stone-li/corefx,fffej/corefx,dhoehna/corefx,larsbj1988/corefx,the-dwyer/corefx,rjxby/corefx,weltkante/corefx,destinyclown/corefx,nbarbettini/corefx,rahku/corefx,josguil/corefx,Chrisboh/corefx,ravimeda/corefx,lggomez/corefx,zhangwenquan/corefx,JosephTremoulet/corefx,weltkante/corefx,Ermiar/corefx,gkhanna79/corefx,uhaciogullari/corefx,shimingsg/corefx,axelheer/corefx,viniciustaveira/corefx,weltkante/corefx,alphonsekurian/corefx,Priya91/corefx-1,elijah6/corefx,BrennanConroy/corefx,chenkennt/corefx,ericstj/corefx,josguil/corefx,richlander/corefx,wtgodbe/corefx,mafiya69/corefx,brett25/corefx,pallavit/corefx,marksmeltzer/corefx,twsouthwick/corefx,vrassouli/corefx,rajansingh10/corefx,parjong/corefx,matthubin/corefx,690486439/corefx,seanshpark/corefx,krytarowski/corefx,shrutigarg/corefx,scott156/corefx,rubo/corefx,Chrisboh/corefx,ViktorHofer/corefx,zhenlan/corefx,zmaruo/corefx,heXelium/corefx,VPashkov/corefx,alexandrnikitin/corefx,jlin177/corefx,benjamin-bader/corefx,fffej/corefx,MaggieTsang/corefx,cydhaselton/corefx,jlin177/corefx,PatrickMcDonald/corefx,dsplaisted/corefx,shmao/corefx,iamjasonp/corefx,marksmeltzer/corefx,Ermiar/corefx,mazong1123/corefx,rjxby/corefx,krytarowski/corefx,the-dwyer/corefx,seanshpark/corefx,benjamin-bader/corefx,manu-silicon/corefx,pgavlin/corefx,ptoonen/corefx,Chrisboh/corefx,stone-li/corefx,pallavit/corefx,YoupHulsebos/corefx,n1ghtmare/corefx,dsplaisted/corefx,uhaciogullari/corefx,Petermarcu/corefx,bitcrazed/corefx,benjamin-bader/corefx,gabrielPeart/corefx,chaitrakeshav/corefx,JosephTremoulet/corefx,alexandrnikitin/corefx,VPashkov/corefx,lggomez/corefx,comdiv/corefx,pallavit/corefx,Priya91/corefx-1,fffej/corefx,alexandrnikitin/corefx,ellismg/corefx,ravimeda/corefx,parjong/corefx,nbarbettini/corefx,vs-team/corefx,oceanho/corefx,seanshpark/corefx,mafiya69/corefx,mmitche/corefx,billwert/corefx,mafiya69/corefx,lydonchandra/corefx,mmitche/corefx,bpschoch/corefx,ericstj/corefx,scott156/corefx,n1ghtmare/corefx,mafiya69/corefx,rjxby/corefx,shmao/corefx,alexperovich/corefx,parjong/corefx,jeremymeng/corefx,fgreinacher/corefx,claudelee/corefx,chenxizhang/corefx,manu-silicon/corefx,zhangwenquan/corefx,JosephTremoulet/corefx,BrennanConroy/corefx,spoiledsport/corefx,janhenke/corefx,dhoehna/corefx,rahku/corefx,erpframework/corefx,dkorolev/corefx,DnlHarvey/corefx,ptoonen/corefx,mellinoe/corefx,jeremymeng/corefx,shana/corefx,Winsto/corefx,jeremymeng/corefx,chaitrakeshav/corefx,ptoonen/corefx,nchikanov/corefx,rjxby/corefx,dtrebbien/corefx,alexperovich/corefx,rubo/corefx,ravimeda/corefx,popolan1986/corefx,mazong1123/corefx,rjxby/corefx,parjong/corefx,alexperovich/corefx,Frank125/corefx,thiagodin/corefx,thiagodin/corefx,mafiya69/corefx,mafiya69/corefx,shrutigarg/corefx,cnbin/corefx,shrutigarg/corefx,vs-team/corefx,richlander/corefx,vidhya-bv/corefx-sorting,Yanjing123/corefx,ericstj/corefx,josguil/corefx,alexperovich/corefx,rubo/corefx,axelheer/corefx,stormleoxia/corefx,tijoytom/corefx,vijaykota/corefx,shimingsg/corefx,khdang/corefx,gkhanna79/corefx,marksmeltzer/corefx,ericstj/corefx,comdiv/corefx,YoupHulsebos/corefx,dsplaisted/corefx,MaggieTsang/corefx,cydhaselton/corefx,thiagodin/corefx,mmitche/corefx,wtgodbe/corefx,shana/corefx,fffej/corefx,zmaruo/corefx,dotnet-bot/corefx,ellismg/corefx,stephenmichaelf/corefx,krk/corefx,stephenmichaelf/corefx,nchikanov/corefx,Priya91/corefx-1,Jiayili1/corefx,ellismg/corefx,manu-silicon/corefx,Petermarcu/corefx,manu-silicon/corefx,krk/corefx,vijaykota/corefx,n1ghtmare/corefx,690486439/corefx,popolan1986/corefx,PatrickMcDonald/corefx,krk/corefx,iamjasonp/corefx,janhenke/corefx,tijoytom/corefx,DnlHarvey/corefx,destinyclown/corefx,Chrisboh/corefx,lggomez/corefx,anjumrizwi/corefx,ericstj/corefx,andyhebear/corefx,krk/corefx,krk/corefx,dotnet-bot/corefx,parjong/corefx,weltkante/corefx,bitcrazed/corefx,zhangwenquan/corefx,iamjasonp/corefx,xuweixuwei/corefx,rahku/corefx,ellismg/corefx,popolan1986/corefx,gkhanna79/corefx,VPashkov/corefx,fernando-rodriguez/corefx,stone-li/corefx,benpye/corefx,nelsonsar/corefx