R=titzer@chromium.org

Bug: v8:6600
Change-Id: I2eb914e7558c01d924cb9d39f18e1c3a5f5c72e5
Reviewed-on: https://chromium-review.googlesource.com/1035123Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52912}