Performed manual testing as well by making 20 CPU profile recordings of
loading http://meduza.io page. Without the patch the page renderer memory size
grows beyond 300MB. With the patch it remains below 200MB.

BUG=v8:6623

Change-Id: Ifce541b84bb2aaaa5175520f8dd49dbc0cb5dd20
Reviewed-on: https://chromium-review.googlesource.com/798020
Commit-Queue: Alexei Filippov <alph@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49914}