R=titzer@chromium.org
BUG=v8:6408

Change-Id: I277beafaace334883ddbe63b9615e3f18085ce5e
Reviewed-on: https://chromium-review.googlesource.com/1186411
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55350}