This reverts commit ac3c4fcf.

Reason for revert: Tested this CL for backport.

Original change's description:
> [heap] Disable old-to-new invalidation
> 
> Disable invalidation of old-to-new slots for now. Invalidation doesn't
> match behavior of clearing slots directly in the remembered set.
> 
> Bug: chromium:1004365
> Change-Id: Ib6a21457827faafa75be88720c214e5ec483c71b
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1813028
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#63890}

TBR=ulan@chromium.org,dinfuehr@chromium.org

Change-Id: Id3d210cd970ea7b8e28571b7801b7a395e4f0af3
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:1004365
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1813745Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63891}