Otherwise we'll get weird semantics when enumerating objects after many
deletes/reinserts.

Bug: chromium:1033771
Change-Id: If0a459169c3794a30d9632d09e80da3cfcd4302c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1993966
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65690}