BUG=v8:6478, chromium:729768

R=bradnelson@chromium.org, eholk@chromium.org

Review-Url: https://codereview.chromium.org/2903153002
Cr-Original-Commit-Position: refs/heads/master@{#45931}
Committed: https://chromium.googlesource.com/v8/v8/+/7e6ed62071d2756688a23bd6dac096b0d4660b5d
Review-Url: https://codereview.chromium.org/2903153002
Cr-Commit-Position: refs/heads/master@{#45967}