This is a reland of 4f051fd5

Relanding because last revert was caused by unrelated flakes.

Original change's description:
> [ptr-compr][x64] Temporarily enable pointer compression on x64
>
> ... and make sure that the x64 ptr-compr bots proceed testing V8 without
> pointer compression in order to keep testing the full pointer mode.
>
> Cq-Include-Trybots: luci.v8.try:v8_linux64_ubsan_rel_ng,v8_linux64_tsan_rel
> Bug: v8:7703
> Change-Id: Ied4e7bacf99c9d63e0459613fec522273f595de8
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1523327
> Commit-Queue: Igor Sheludko <ishell@chromium.org>
> Auto-Submit: Leszek Swirski <leszeks@chromium.org>
> Reviewed-by: Michael Achenbach <machenbach@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#60339}

Bug: v8:7703
Change-Id: I9c588de77070d4fbf1bb1a21ae58c398a22eed9c
Cq-Include-Trybots: luci.v8.try:v8_linux64_ubsan_rel_ng, v8_linux64_tsan_rel, v8_mac64_gc_stress_dbg
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1530819
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60370}