swift234

ARCOpt: fix an object ownership bug.
When checking for users of an object we need to consider all values
because any use of the object may increase its lifetime. 

For example, in the sil code below, instruction %26 increases the lifetime of
object %9. If we remove the retain-release pair then the apply inst may
release %9 and the load would become invalid. 

  strong_retain %9#0 : $Builtin.ObjectPointer
  %24 = apply %19<>()
  %26 = load %9#1 : $*Int
  strong_release %9#0 : $Builtin.ObjectPointer
  return %26 : $Int

This fixes rdar://16233340



Swift SVN r14745