titzer@ originally created this
CL (https://codereview.chromium.org/2757903002). I fixed crashing tests
and adressed some comments of the reviewers.

R=bradnelson@chromium.org, clemensh@chromium.org, mtrofin@chromium.org
BUG=v8:6003

Change-Id: I4ab6d503909402d24043657a896200032e6d1023
Reviewed-on: https://chromium-review.googlesource.com/464887Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Mircea Trofin <mtrofin@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44333}