AST: Remove some dead code from LayoutConstraint.h
AST: Remove some dead code from LayoutConstraint.h

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