[Runtime] Copy the value witness table pointer manually.
[Runtime] Copy the value witness table pointer manually.

Fixes rdar://74136916.

apple/swift,JGiola/swift,benlangmuir/swift,gregomni/swift,tkremenek/swift,tkremenek/swift,atrick/swift,parkera/swift,rudkx/swift,glessard/swift,JGiola/swift,xwu/swift,xwu/swift,tkremenek/swift,tkremenek/swift,ahoppen/swift,apple/swift,xwu/swift,roambotics/swift,atrick/swift,parkera/swift,ahoppen/swift,JGiola/swift,atrick/swift,roambotics/swift,xwu/swift,gregomni/swift,benlangmuir/swift,JGiola/swift,atrick/swift,benlangmuir/swift,gregomni/swift,xwu/swift,ahoppen/swift,xwu/swift,glessard/swift,tkremenek/swift,parkera/swift,JGiola/swift,hooman/swift,glessard/swift,rudkx/swift,hooman/swift,ahoppen/swift,parkera/swift,ahoppen/swift,roambotics/swift,glessard/swift,gregomni/swift,apple/swift,glessard/swift,benlangmuir/swift,tkremenek/swift,roambotics/swift,gregomni/swift,apple/swift,benlangmuir/swift,atrick/swift,parkera/swift,rudkx/swift,hooman/swift,hooman/swift,JGiola/swift,hooman/swift,hooman/swift,apple/swift,tkremenek/swift,parkera/swift,ahoppen/swift,roambotics/swift,benlangmuir/swift,parkera/swift,xwu/swift,gregomni/swift,atrick/swift,rudkx/swift,apple/swift,glessard/swift,hooman/swift,parkera/swift,rudkx/swift,rudkx/swift,roambotics/swift