R=titzer@chromium.org

Bug: v8:7965
Change-Id: I5e44e8a4dd522703e7a20e32abae1f66ba44451e
Reviewed-on: https://chromium-review.googlesource.com/1148566Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54661}