This is a reland of f5611402

We had to revert due to branch cut. The A/B experiment wasn't done yet.

Original change's description:
> [ptr-compr][arm64] Temporarily enable pointer compression on arm64
>
> ... and make sure that the arm64 ptr-compr bots proceed testing V8 without
> pointer compression in order to keep testing the other config.
>
> Commented out the 'extra' variant since it was crashing. Opened a bug
> regarding that: https://bugs.chromium.org/p/v8/issues/detail?id=9568
>
> Similar to x64's https://chromium-review.googlesource.com/c/v8/v8/+/1607654
>
> Bug: v8:7703
> Change-Id: Ifd46b029bab34524f9f536dcdbd1574f2ddcbf37
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1724216
> Reviewed-by: Tamer Tas <tmrts@chromium.org>
> Reviewed-by: Michael Achenbach <machenbach@chromium.org>
> Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#63019}

Bug: v8:7703
Change-Id: I28726f534dfd17dd695a3ba5653873368e7a44b0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1872403Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64459}