Hide standard error from taskkill as well.
Hide standard error from taskkill as well.

In cases where there's no process to kill, TaskKill will write a
message with the words "ERROR:" to standard error. This will cause
MSBuild (when invoking cibuild.cmd as part of a composed build) to
think that the Roslyn sub-build failed.

robinsedlaczek/roslyn,MichalStrehovsky/roslyn,kelltrick/roslyn,tvand7093/roslyn,jkotas/roslyn,tmat/roslyn,khyperia/roslyn,TyOverby/roslyn,VSadov/roslyn,paulvanbrenk/roslyn,pdelvo/roslyn,cston/roslyn,tmat/roslyn,wvdd007/roslyn,TyOverby/roslyn,Hosch250/roslyn,bkoelman/roslyn,KevinRansom/roslyn,brettfo/roslyn,tmat/roslyn,davkean/roslyn,ErikSchierboom/roslyn,xasx/roslyn,davkean/roslyn,paulvanbrenk/roslyn,aelij/roslyn,tmeschter/roslyn,drognanar/roslyn,CyrusNajmabadi/roslyn,gafter/roslyn,jasonmalinowski/roslyn,reaction1989/roslyn,orthoxerox/roslyn,tmeschter/roslyn,pdelvo/roslyn,akrisiun/roslyn,swaroop-sridhar/roslyn,physhi/roslyn,brettfo/roslyn,AdamSpeight2008/roslyn-AdamSpeight2008,mattscheffer/roslyn,weltkante/roslyn,srivatsn/roslyn,lorcanmooney/roslyn,ErikSchierboom/roslyn,Hosch250/roslyn,physhi/roslyn,shyamnamboodiripad/roslyn,mmitche/roslyn,AnthonyDGreen/roslyn,nguerrera/roslyn,AlekseyTs/roslyn,tannergooding/roslyn,yeaicc/roslyn,mgoertz-msft/roslyn,mgoertz-msft/roslyn,AnthonyDGreen/roslyn,heejaechang/roslyn,CaptainHayashi/roslyn,KirillOsenkov/roslyn,srivatsn/roslyn,aelij/roslyn,jmarolf/roslyn,lorcanmooney/roslyn,AdamSpeight2008/roslyn-AdamSpeight2008,abock/roslyn,bbarry/roslyn,wvdd007/roslyn,AmadeusW/roslyn,mavasani/roslyn,tvand7093/roslyn,eriawan/roslyn,sharwell/roslyn,diryboy/roslyn,CyrusNajmabadi/roslyn,heejaechang/roslyn,jcouv/roslyn,AlekseyTs/roslyn,dotnet/roslyn,panopticoncentral/roslyn,drognanar/roslyn,yeaicc/roslyn,mmitche/roslyn,mavasani/roslyn,jamesqo/roslyn,mattwar/roslyn,wvdd007/roslyn,robinsedlaczek/roslyn,MattWindsor91/roslyn,jkotas/roslyn,CyrusNajmabadi/roslyn,mattscheffer/roslyn,sharwell/roslyn,jeffanders/roslyn,Giftednewt/roslyn,dotnet/roslyn,khyperia/roslyn,mattscheffer/roslyn,kelltrick/roslyn,nguerrera/roslyn,VSadov/roslyn,tannergooding/roslyn,diryboy/roslyn,reaction1989/roslyn,diryboy/roslyn,stephentoub/roslyn,aelij/roslyn,agocke/roslyn,tvand7093/roslyn,agocke/roslyn,DustinCampbell/roslyn,jasonmalinowski/roslyn,physhi/roslyn,Hosch250/roslyn,ErikSchierboom/roslyn,zooba/roslyn,bartdesmet/roslyn,dpoeschl/roslyn,heejaechang/roslyn,abock/roslyn,DustinCampbell/roslyn,jmarolf/roslyn,KevinRansom/roslyn,jasonmalinowski/roslyn,dotnet/roslyn,panopticoncentral/roslyn,mattwar/roslyn,jcouv/roslyn,jcouv/roslyn,weltkante/roslyn,tannergooding/roslyn,weltkante/roslyn,brettfo/roslyn,eriawan/roslyn,MichalStrehovsky/roslyn,orthoxerox/roslyn,AmadeusW/roslyn,bartdesmet/roslyn,gafter/roslyn,lorcanmooney/roslyn,tmeschter/roslyn,mgoertz-msft/roslyn,shyamnamboodiripad/roslyn,abock/roslyn,pdelvo/roslyn,agocke/roslyn,stephentoub/roslyn,bartdesmet/roslyn,swaroop-sridhar/roslyn,xasx/roslyn,sharwell/roslyn,bkoelman/roslyn,khyperia/roslyn,dpoeschl/roslyn,amcasey/roslyn,dpoeschl/roslyn,yeaicc/roslyn,mattwar/roslyn,stephentoub/roslyn,OmarTawfik/roslyn,drognanar/roslyn,srivatsn/roslyn,AnthonyDGreen/roslyn,bbarry/roslyn,akrisiun/roslyn,MattWindsor91/roslyn,genlu/roslyn,cston/roslyn,mmitche/roslyn,eriawan/roslyn,panopticoncentral/roslyn,jmarolf/roslyn,robinsedlaczek/roslyn,amcasey/roslyn,AdamSpeight2008/roslyn-AdamSpeight2008,AmadeusW/roslyn,CaptainHayashi/roslyn,DustinCampbell/roslyn,zooba/roslyn,amcasey/roslyn,orthoxerox/roslyn,paulvanbrenk/roslyn,KirillOsenkov/roslyn,KirillOsenkov/roslyn,TyOverby/roslyn,mavasani/roslyn,nguerrera/roslyn,jamesqo/roslyn,MichalStrehovsky/roslyn,Giftednewt/roslyn,KevinRansom/roslyn,jkotas/roslyn,xasx/roslyn,OmarTawfik/roslyn,CaptainHayashi/roslyn,MattWindsor91/roslyn,gafter/roslyn,jeffanders/roslyn,AlekseyTs/roslyn,bkoelman/roslyn,kelltrick/roslyn,OmarTawfik/roslyn,cston/roslyn,genlu/roslyn,VSadov/roslyn,jeffanders/roslyn,jamesqo/roslyn,akrisiun/roslyn,bbarry/roslyn,Giftednewt/roslyn,zooba/roslyn,swaroop-sridhar/roslyn,genlu/roslyn,MattWindsor91/roslyn,davkean/roslyn,shyamnamboodiripad/roslyn,reaction1989/roslyn