Will be needed in a follow-up (the constants cache builder needs to
grow arrays in old space).

Bug: v8:6666
Change-Id: Ibd911ffd30e2b0f43881e649b5601111d23e4509
Reviewed-on: https://chromium-review.googlesource.com/924068Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51326}