Pass -prerelease to the vswhere query
Pass -prerelease to the vswhere query

On our 15.8 machines, there aren't release versions...because we haven't
released it yet.

brettfo/roslyn,swaroop-sridhar/roslyn,ErikSchierboom/roslyn,VSadov/roslyn,KevinRansom/roslyn,mavasani/roslyn,abock/roslyn,KirillOsenkov/roslyn,panopticoncentral/roslyn,eriawan/roslyn,bartdesmet/roslyn,jmarolf/roslyn,nguerrera/roslyn,swaroop-sridhar/roslyn,aelij/roslyn,DustinCampbell/roslyn,eriawan/roslyn,reaction1989/roslyn,nguerrera/roslyn,brettfo/roslyn,diryboy/roslyn,brettfo/roslyn,AmadeusW/roslyn,VSadov/roslyn,physhi/roslyn,gafter/roslyn,jasonmalinowski/roslyn,stephentoub/roslyn,AlekseyTs/roslyn,physhi/roslyn,aelij/roslyn,swaroop-sridhar/roslyn,agocke/roslyn,abock/roslyn,davkean/roslyn,CyrusNajmabadi/roslyn,davkean/roslyn,DustinCampbell/roslyn,panopticoncentral/roslyn,heejaechang/roslyn,weltkante/roslyn,shyamnamboodiripad/roslyn,dotnet/roslyn,stephentoub/roslyn,sharwell/roslyn,jasonmalinowski/roslyn,agocke/roslyn,MichalStrehovsky/roslyn,panopticoncentral/roslyn,CyrusNajmabadi/roslyn,aelij/roslyn,dotnet/roslyn,diryboy/roslyn,agocke/roslyn,tannergooding/roslyn,xasx/roslyn,DustinCampbell/roslyn,AlekseyTs/roslyn,jcouv/roslyn,stephentoub/roslyn,tmat/roslyn,xasx/roslyn,weltkante/roslyn,KevinRansom/roslyn,mavasani/roslyn,CyrusNajmabadi/roslyn,mavasani/roslyn,sharwell/roslyn,jasonmalinowski/roslyn,genlu/roslyn,mgoertz-msft/roslyn,heejaechang/roslyn,dotnet/roslyn,mgoertz-msft/roslyn,genlu/roslyn,jcouv/roslyn,gafter/roslyn,heejaechang/roslyn,KevinRansom/roslyn,mgoertz-msft/roslyn,tmat/roslyn,KirillOsenkov/roslyn,bartdesmet/roslyn,jcouv/roslyn,reaction1989/roslyn,wvdd007/roslyn,davkean/roslyn,shyamnamboodiripad/roslyn,eriawan/roslyn,reaction1989/roslyn,sharwell/roslyn,diryboy/roslyn,abock/roslyn,jmarolf/roslyn,wvdd007/roslyn,jmarolf/roslyn,ErikSchierboom/roslyn,xasx/roslyn,tannergooding/roslyn,wvdd007/roslyn,nguerrera/roslyn,tannergooding/roslyn,MichalStrehovsky/roslyn,ErikSchierboom/roslyn,MichalStrehovsky/roslyn,tmat/roslyn,gafter/roslyn,genlu/roslyn,KirillOsenkov/roslyn,AlekseyTs/roslyn,weltkante/roslyn,physhi/roslyn,VSadov/roslyn,bartdesmet/roslyn,shyamnamboodiripad/roslyn,AmadeusW/roslyn,AmadeusW/roslyn