Merge "Relax CAS in some uses of Object::AtomicSetReadBarrierPointer." am: 16cabc4acd am: ae1afa423b
am: 03ce45f1d5

* commit '03ce45f1d5d9550984e60b68a785758dd79ac2e8':
  Relax CAS in some uses of Object::AtomicSetReadBarrierPointer.