R=titzer@chromium.org
BUG=v8:7754,v8:7490

Change-Id: Ib6d34c1716f9f877c7e04391ee59c2a12df2d0d3
Reviewed-on: https://chromium-review.googlesource.com/1054873Reviewed-by: Ben Titzer <titzer@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53126}