build: remove unnecessary `CXX_STANDARD` for Windows
build: remove unnecessary `CXX_STANDARD` for Windows

The entire project is now at C++14.  Windows had to adopt C++14 earlier
to support processing the Windows SDK headers.  This is no longer
necessary, adopt the global settings instead.

tkremenek/swift,hooman/swift,jmgc/swift,tkremenek/swift,roambotics/swift,roambotics/swift,apple/swift,allevato/swift,jckarter/swift,atrick/swift,apple/swift,nathawes/swift,airspeedswift/swift,atrick/swift,parkera/swift,hooman/swift,ahoppen/swift,xwu/swift,JGiola/swift,nathawes/swift,hooman/swift,hooman/swift,CodaFi/swift,atrick/swift,jmgc/swift,rudkx/swift,atrick/swift,airspeedswift/swift,nathawes/swift,benlangmuir/swift,jmgc/swift,benlangmuir/swift,stephentyrone/swift,ahoppen/swift,ahoppen/swift,glessard/swift,parkera/swift,tkremenek/swift,airspeedswift/swift,jckarter/swift,CodaFi/swift,rudkx/swift,CodaFi/swift,airspeedswift/swift,CodaFi/swift,hooman/swift,airspeedswift/swift,roambotics/swift,glessard/swift,allevato/swift,JGiola/swift,parkera/swift,jmgc/swift,hooman/swift,parkera/swift,benlangmuir/swift,glessard/swift,xwu/swift,jmgc/swift,JGiola/swift,allevato/swift,atrick/swift,stephentyrone/swift,gregomni/swift,rudkx/swift,tkremenek/swift,xwu/swift,stephentyrone/swift,airspeedswift/swift,parkera/swift,tkremenek/swift,rudkx/swift,gregomni/swift,glessard/swift,xwu/swift,stephentyrone/swift,benlangmuir/swift,glessard/swift,CodaFi/swift,rudkx/swift,airspeedswift/swift,roambotics/swift,nathawes/swift,apple/swift,jmgc/swift,jmgc/swift,hooman/swift,gregomni/swift,stephentyrone/swift,allevato/swift,benlangmuir/swift,ahoppen/swift,gregomni/swift,tkremenek/swift,nathawes/swift,nathawes/swift,parkera/swift,jckarter/swift,xwu/swift,apple/swift,glessard/swift,xwu/swift,allevato/swift,allevato/swift,parkera/swift,ahoppen/swift,JGiola/swift,xwu/swift,allevato/swift,roambotics/swift,stephentyrone/swift,stephentyrone/swift,jckarter/swift,JGiola/swift,CodaFi/swift,roambotics/swift,jckarter/swift,atrick/swift,apple/swift,apple/swift,ahoppen/swift,gregomni/swift,nathawes/swift,jckarter/swift,CodaFi/swift,JGiola/swift,tkremenek/swift,parkera/swift,benlangmuir/swift,jckarter/swift,rudkx/swift,gregomni/swift