Clean-up a couple of CAS loops to avoid loading after a compare_exchange
(which updates the old value), and to loosen the memory ordering to
acquire-release to avoid unnecessary fences.

Change-Id: Ifb8e5e5136f687ca5a71417a5d131a7023add054
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2050390
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66235}