R=jgruber@chromium.org

Bug: v8:7227, v8:7228
Change-Id: I2c567a6bf4a3d1128559ae440182bd14fb78d005
Reviewed-on: https://chromium-review.googlesource.com/832462
Commit-Queue: Yang Guo <yangguo@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50198}