BUG=v8:6949,v8:9396

Change-Id: Icd65e16f6b5b41ad56d1b8767a73e8ca15d05b74
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1807365
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Mythri Alle <mythria@chromium.org>
Reviewed-by: Sathya Gunasekaran  <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63845}