Update WindowsBuild.md
Update WindowsBuild.md

Prepend to the path rather than append to ensure that the new compiler is picked up.  Thanks to @lanza for pointing this out.
devincoughlin/swift,gribozavr/swift,xwu/swift,devincoughlin/swift,JGiola/swift,gribozavr/swift,karwa/swift,nathawes/swift,benlangmuir/swift,jmgc/swift,apple/swift,ahoppen/swift,xedin/swift,jmgc/swift,parkera/swift,jmgc/swift,xedin/swift,rudkx/swift,hooman/swift,tkremenek/swift,xedin/swift,gregomni/swift,jmgc/swift,atrick/swift,aschwaighofer/swift,glessard/swift,gribozavr/swift,roambotics/swift,tkremenek/swift,shahmishal/swift,parkera/swift,glessard/swift,devincoughlin/swift,practicalswift/swift,xedin/swift,aschwaighofer/swift,roambotics/swift,gribozavr/swift,stephentyrone/swift,atrick/swift,allevato/swift,amraboelela/swift,hooman/swift,karwa/swift,shajrawi/swift,karwa/swift,practicalswift/swift,practicalswift/swift,harlanhaskins/swift,atrick/swift,sschiau/swift,aschwaighofer/swift,harlanhaskins/swift,lorentey/swift,CodaFi/swift,lorentey/swift,rudkx/swift,rudkx/swift,benlangmuir/swift,JGiola/swift,jckarter/swift,lorentey/swift,amraboelela/swift,devincoughlin/swift,gregomni/swift,practicalswift/swift,roambotics/swift,nathawes/swift,lorentey/swift,airspeedswift/swift,tkremenek/swift,roambotics/swift,xwu/swift,roambotics/swift,jckarter/swift,shajrawi/swift,shahmishal/swift,nathawes/swift,CodaFi/swift,karwa/swift,jmgc/swift,xwu/swift,xwu/swift,gribozavr/swift,gregomni/swift,gribozavr/swift,harlanhaskins/swift,xedin/swift,stephentyrone/swift,hooman/swift,stephentyrone/swift,xedin/swift,CodaFi/swift,allevato/swift,sschiau/swift,allevato/swift,xwu/swift,hooman/swift,jckarter/swift,airspeedswift/swift,rudkx/swift,airspeedswift/swift,lorentey/swift,allevato/swift,gribozavr/swift,karwa/swift,shajrawi/swift,harlanhaskins/swift,shahmishal/swift,airspeedswift/swift,gregomni/swift,stephentyrone/swift,JGiola/swift,jckarter/swift,lorentey/swift,glessard/swift,rudkx/swift,airspeedswift/swift,parkera/swift,airspeedswift/swift,shajrawi/swift,sschiau/swift,CodaFi/swift,jmgc/swift,allevato/swift,benlangmuir/swift,devincoughlin/swift,sschiau/swift,glessard/swift,roambotics/swift,practicalswift/swift,xedin/swift,shahmishal/swift,hooman/swift,jmgc/swift,jckarter/swift,sschiau/swift,rudkx/swift,practicalswift/swift,nathawes/swift,ahoppen/swift,stephentyrone/swift,ahoppen/swift,tkremenek/swift,shajrawi/swift,amraboelela/swift,glessard/swift,tkremenek/swift,apple/swift,atrick/swift,parkera/swift,harlanhaskins/swift,aschwaighofer/swift,nathawes/swift,xwu/swift,CodaFi/swift,benlangmuir/swift,karwa/swift,parkera/swift,aschwaighofer/swift,shahmishal/swift,CodaFi/swift,ahoppen/swift,gregomni/swift,gribozavr/swift,glessard/swift,shajrawi/swift,JGiola/swift,benlangmuir/swift,atrick/swift,airspeedswift/swift,karwa/swift,amraboelela/swift,gregomni/swift,amraboelela/swift,shahmishal/swift,sschiau/swift,aschwaighofer/swift,parkera/swift,stephentyrone/swift,JGiola/swift,tkremenek/swift,practicalswift/swift,apple/swift,JGiola/swift,apple/swift,devincoughlin/swift,stephentyrone/swift,parkera/swift,lorentey/swift,karwa/swift,xwu/swift,nathawes/swift,devincoughlin/swift,allevato/swift,hooman/swift,apple/swift,shahmishal/swift,harlanhaskins/swift,atrick/swift,CodaFi/swift,jckarter/swift,ahoppen/swift,harlanhaskins/swift,shajrawi/swift,practicalswift/swift,shahmishal/swift,tkremenek/swift,aschwaighofer/swift,ahoppen/swift,benlangmuir/swift,sschiau/swift,apple/swift,shajrawi/swift,xedin/swift,hooman/swift,lorentey/swift,nathawes/swift,devincoughlin/swift,sschiau/swift,allevato/swift,amraboelela/swift,jckarter/swift,amraboelela/swift,parkera/swift