[SSADestroyHoisting] Recombine store [init]s.
[SSADestroyHoisting] Recombine store [init]s.

Before hoisting destroy_addrs, we split store [assign]s into
destroy_addrs and store [init]s.  If those destroy_addrs were not able
to be hoisted, though, recombine the two back into a store [assign].
Doing so avoids introducing extra ARC traffic.

roambotics/swift,ahoppen/swift,JGiola/swift,ahoppen/swift,rudkx/swift,atrick/swift,gregomni/swift,glessard/swift,apple/swift,gregomni/swift,roambotics/swift,atrick/swift,rudkx/swift,rudkx/swift,roambotics/swift,ahoppen/swift,ahoppen/swift,glessard/swift,apple/swift,apple/swift,JGiola/swift,benlangmuir/swift,gregomni/swift,atrick/swift,rudkx/swift,rudkx/swift,benlangmuir/swift,JGiola/swift,atrick/swift,glessard/swift,JGiola/swift,gregomni/swift,glessard/swift,apple/swift,roambotics/swift,benlangmuir/swift,roambotics/swift,glessard/swift,gregomni/swift,atrick/swift,roambotics/swift,rudkx/swift,JGiola/swift,gregomni/swift,apple/swift,atrick/swift,ahoppen/swift,apple/swift,benlangmuir/swift,glessard/swift,benlangmuir/swift,benlangmuir/swift,ahoppen/swift,JGiola/swift