This reverts commit 2d710200.

Reason for revert: It's not ready for shipping in M76.

> Reland "[ptr-compr][x64] Temporarily enable pointer compression on x64"
>
> This is a reland of d61a9347
>
> 6th attempt. Relanding after fixing TSan/UBSan 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
> > Change-Id: Ib1498609603cb03be2464043658131d5a2f1e012
> > 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,mac-rel
> > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1559850
> > Commit-Queue: Igor Sheludko <ishell@chromium.org>
> > Reviewed-by: Michael Achenbach <machenbach@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#61416}
>
> Bug: v8:7703
> Change-Id: I1fa0989aef9ea08e54fd6dfd32d6989367332ce3
> Cq-Include-Trybots: luci.v8.try:v8_linux64_ubsan_rel_ng,v8_linux64_tsan_rel
> Cq-Include-Trybots: luci.v8.try:v8_linux64_cfi_rel_ng
> Cq-Include-Trybots: luci.chromium.try:fuchsia_x64,linux-rel,mac-rel
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1607654
> Commit-Queue: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Michael Achenbach <machenbach@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#61559}

Tbr: machenbach@chromium.org
Bug: v8:7703
Change-Id: Ic73b57203bbcb637e33b3577ce8142d43c364796
Cq-Include-Trybots: luci.v8.try:v8_linux64_ubsan_rel_ng,v8_linux64_tsan_rel
Cq-Include-Trybots: luci.v8.try:v8_linux64_cfi_rel_ng
Cq-Include-Trybots: luci.chromium.try:fuchsia_x64,linux-rel,mac-rel
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1621942
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61740}