This avoids emitting the costly barriers on arm.

Bug: chromium:651354
Change-Id: Ibb29e58f7c41aab37ed5c4971b2a754b4ecd7155
Reviewed-on: https://chromium-review.googlesource.com/533337
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46011}