The getter and setter members may be set after initialization; in that
case, use acquire-release semantics.

Bug: v8:7790, chromium:1236965
Change-Id: Ia28c89b664787ff92a56a2f6dcc4d76655df5ff3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3080567Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Auto-Submit: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#76164}