This is a reland of 6604f182

Original change's description:
> [heap] Clean-up keys of oldspace weakmaps during scavenge
>
> This CL adds handling for cleaning up weakmap (EphemeronHashTable)
> keys during scavenge, even if the weakmap resides in oldspace.
>
> Change-Id: If8d711c050ddbcae4dd6e8da549e0c0d08ba47b2
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1523787
> Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
> Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#60432}

CQ_INCLUDE_TRYBOTS=luci.chrome.try:Mac Builder Perf

Change-Id: Ie640f2b0340637a5391fb17ba3c9e6422eaf306a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1541476
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60554}