R=titzer@chromium.org
BUG=v8:7549

Change-Id: Ie77a22f0a6204d673d130be45ca20d5986cddd88
Reviewed-on: https://chromium-review.googlesource.com/962423
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51928}