R=jkummerow@chromium.org

Bug: v8:7505, v8:6791
Change-Id: I11b0031dfafa499a813e3e52080ee5542224799a
Reviewed-on: https://chromium-review.googlesource.com/941130Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51639}