This reverts commit 589d1a6b.

Reason for revert: Breaking UBSan - https://ci.chromium.org/p/v8/builders/ci/V8%20Linux64%20UBSan/5219

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.
> 
> Bug: v8:7703
> Change-Id: Iee725deda813425a6f0722948b54976154f50909
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1497139
> Reviewed-by: Michael Hablich <hablich@chromium.org>
> Reviewed-by: Michael Achenbach <machenbach@chromium.org>
> Commit-Queue: Michael Achenbach <machenbach@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#60230}

TBR=machenbach@chromium.org,hablich@chromium.org,ishell@chromium.org,verwaest@chromium.org

Change-Id: I5a9f04acba1ef23ae944d97a029ea018808c7fcb
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7703
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1522991Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60231}