This reverts commit 42beed97.

Reason for revert: This commit seems to cause consistent failures in
some ProcessMemoryMetricsEmitterTest tests on Mac and ChromeOS. I'm
not sure what the exact reasoning behind this is. See https://crbug.com/949157.

Original change's description:
> Reland "[ptr-compr][x64] Temporarily enable pointer compression on x64"
>
> This is a reland of 4f051fd5
>
> Relanding after fixing Chromium issues.
>
> 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
> > Cq-Include-Trybots: luci.v8.try:v8_linux64_ubsan_rel_ng,v8_linux64_tsan_rel
> > 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}
>
> Bug: v8:7703
> Change-Id: Ic2d1c2ae41ec645f34963f5f561c33199c72ef4b
> Cq-Include-Trybots: luci.v8.try:v8_linux64_ubsan_rel_ng,v8_linux64_tsan_rel
> Cq-Include-Trybots: luci.chromium.try:fuchsia_x64,linux-rel
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1535819
> Commit-Queue: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Michael Achenbach <machenbach@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#60582}

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

Change-Id: Ib9737081e90dddcfe44af9da1275a610da209323
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7703
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1550709
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60618}