Add test case for typelayout based value witness emission.
Add test case for typelayout based value witness emission.

rdar://51988441

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