Didn't seem to help and caused a couple of regressions.

BUG=v8:6243,chromium:740124

Change-Id: I72887ba245a524211dbf181c77d0cdc6d917d090
Reviewed-on: https://chromium-review.googlesource.com/568480
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Mythri Alle <mythria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46608}