Update WindowsBuild.md
Update WindowsBuild.md

Add instructions to enable tests on Windows.  This requires additional patches to libdispatch and Foundation to enable the build as well as run.  But, this is in preparation for those changes to get merged and for others to replicate the test suite.
jckarter/swift,karwa/swift,roambotics/swift,gregomni/swift,roambotics/swift,ahoppen/swift,apple/swift,jmgc/swift,jmgc/swift,karwa/swift,parkera/swift,allevato/swift,devincoughlin/swift,sschiau/swift,jmgc/swift,JGiola/swift,shahmishal/swift,aschwaighofer/swift,lorentey/swift,CodaFi/swift,sschiau/swift,CodaFi/swift,ahoppen/swift,gregomni/swift,airspeedswift/swift,xwu/swift,xwu/swift,jmgc/swift,gribozavr/swift,apple/swift,aschwaighofer/swift,sschiau/swift,CodaFi/swift,devincoughlin/swift,atrick/swift,shajrawi/swift,harlanhaskins/swift,shajrawi/swift,CodaFi/swift,hooman/swift,sschiau/swift,parkera/swift,CodaFi/swift,JGiola/swift,CodaFi/swift,hooman/swift,karwa/swift,xwu/swift,harlanhaskins/swift,rudkx/swift,harlanhaskins/swift,gribozavr/swift,devincoughlin/swift,jckarter/swift,hooman/swift,xedin/swift,glessard/swift,tkremenek/swift,lorentey/swift,glessard/swift,shajrawi/swift,allevato/swift,xwu/swift,shahmishal/swift,shajrawi/swift,nathawes/swift,stephentyrone/swift,parkera/swift,jmgc/swift,JGiola/swift,benlangmuir/swift,parkera/swift,xedin/swift,tkremenek/swift,glessard/swift,benlangmuir/swift,xedin/swift,karwa/swift,allevato/swift,rudkx/swift,jckarter/swift,apple/swift,karwa/swift,gregomni/swift,benlangmuir/swift,gregomni/swift,xedin/swift,shahmishal/swift,tkremenek/swift,JGiola/swift,harlanhaskins/swift,rudkx/swift,roambotics/swift,devincoughlin/swift,jmgc/swift,xedin/swift,ahoppen/swift,glessard/swift,nathawes/swift,ahoppen/swift,xedin/swift,xedin/swift,gribozavr/swift,airspeedswift/swift,airspeedswift/swift,sschiau/swift,harlanhaskins/swift,shajrawi/swift,atrick/swift,hooman/swift,jckarter/swift,CodaFi/swift,benlangmuir/swift,nathawes/swift,jckarter/swift,airspeedswift/swift,JGiola/swift,karwa/swift,karwa/swift,xedin/swift,JGiola/swift,devincoughlin/swift,gribozavr/swift,shahmishal/swift,jmgc/swift,stephentyrone/swift,nathawes/swift,shahmishal/swift,xwu/swift,shajrawi/swift,lorentey/swift,lorentey/swift,nathawes/swift,aschwaighofer/swift,parkera/swift,stephentyrone/swift,nathawes/swift,roambotics/swift,hooman/swift,tkremenek/swift,tkremenek/swift,ahoppen/swift,parkera/swift,parkera/swift,atrick/swift,atrick/swift,aschwaighofer/swift,glessard/swift,jckarter/swift,glessard/swift,shajrawi/swift,harlanhaskins/swift,lorentey/swift,benlangmuir/swift,atrick/swift,apple/swift,jckarter/swift,atrick/swift,hooman/swift,xwu/swift,gribozavr/swift,allevato/swift,allevato/swift,harlanhaskins/swift,gribozavr/swift,gribozavr/swift,aschwaighofer/swift,apple/swift,shahmishal/swift,stephentyrone/swift,airspeedswift/swift,karwa/swift,tkremenek/swift,rudkx/swift,shahmishal/swift,airspeedswift/swift,roambotics/swift,allevato/swift,ahoppen/swift,roambotics/swift,sschiau/swift,hooman/swift,gribozavr/swift,nathawes/swift,lorentey/swift,rudkx/swift,parkera/swift,sschiau/swift,gregomni/swift,shahmishal/swift,sschiau/swift,devincoughlin/swift,stephentyrone/swift,devincoughlin/swift,shajrawi/swift,airspeedswift/swift,lorentey/swift,aschwaighofer/swift,xwu/swift,stephentyrone/swift,aschwaighofer/swift,rudkx/swift,stephentyrone/swift,benlangmuir/swift,gregomni/swift,tkremenek/swift,allevato/swift,devincoughlin/swift,apple/swift,lorentey/swift