WaitIdAnyExitedNoHangNoWait: handle waitid returning 0 for no waitable children (#39078)
WaitIdAnyExitedNoHangNoWait: handle waitid returning 0 for no waitable children (#39078)

* WaitIdAnyExitedNoHangNoWait: handle waitid returning 0 for no waitable children

* clear using memset

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