to avoid undefined behavior on signed integer overflow.

Change-Id: Ib55b427723a81dddc26f3ce4b2b3b8cc69c9c017
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1782166
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Auto-Submit: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63526}