Porting corefx PR #8179
Porting corefx PR #8179

* Change sync.cmd to use argument parsing logic from build.cmd

iamjasonp/wcf,dotnet/wcf,StephenBonikowsky/wcf,shmao/wcf,imcarolwang/wcf,KKhurin/wcf,zhenlan/wcf,hongdai/wcf,shmao/wcf,StephenBonikowsky/wcf,ElJerry/wcf,hongdai/wcf,dotnet/wcf,zhenlan/wcf,imcarolwang/wcf,iamjasonp/wcf,KKhurin/wcf,dotnet/wcf,MattGal/wcf,MattGal/wcf,ericstj/wcf,ElJerry/wcf,imcarolwang/wcf,mconnew/wcf,ericstj/wcf,mconnew/wcf,mconnew/wcf