fetch_or (lock-prefixed-or on x86) is emulated with branching on
armv7/armv8 and therefore generates more instructions.

This improves android-binary-size by 45K. It should also improve
performance.

Bug: chromium:1238884
Change-Id: I48f59b645a4bb872b3798a1fde11608fd2930ce6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3090342
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Auto-Submit: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#76260}