Such as:
- JSArray (length)
- Root strings, code objects, oddballs

Bug: v8:7790
Change-Id: Ibed83be71b013c090c5a2b6a342c8771ad06916c
Reviewed-on: https://chromium-review.googlesource.com/1215224
Commit-Queue: Georg Neis <neis@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55762}