limit official build to two alpine releases and add Alpine 3.9 to CI (#36392)
limit official build to two alpine releases and add Alpine 3.9 to CI (#36392)

* limit official build to two alpine relases and add Alpine 3.9 to CI as linux-musl sample

* remove quotes around friendly name - it seems escaping \'\(\' is enough.

* move musl_x64_Debug

* fix missing space

shimingsg/corefx,ericstj/corefx,ViktorHofer/corefx,ViktorHofer/corefx,shimingsg/corefx,shimingsg/corefx,wtgodbe/corefx,ericstj/corefx,ViktorHofer/corefx,ericstj/corefx,BrennanConroy/corefx,ViktorHofer/corefx,ViktorHofer/corefx,wtgodbe/corefx,wtgodbe/corefx,wtgodbe/corefx,shimingsg/corefx,ericstj/corefx,ericstj/corefx,BrennanConroy/corefx,shimingsg/corefx,wtgodbe/corefx,wtgodbe/corefx,shimingsg/corefx,shimingsg/corefx,BrennanConroy/corefx,ViktorHofer/corefx,ViktorHofer/corefx,wtgodbe/corefx,ericstj/corefx,ericstj/corefx