This reverts commit 6604f182.

Bug: chromium:945341

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}

TBR=ulan@chromium.org,jarin@chromium.org,sigurds@chromium.org,leszeks@chromium.org

Change-Id: I9dd9b11990a262a457fd1bedc2b45b4a786a81f7
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1538133Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60447}