Revert "Reland "[ptr-compr][x64] Temporarily enable pointer compression on x64""

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}

BUILD.gn

@@ -107,7 +107,7 @@ declare_args() {
   v8_enable_verify_csa = false
 
   # Enable pointer compression (sets -dV8_COMPRESS_POINTERS).
-  v8_enable_pointer_compression = ""
+  v8_enable_pointer_compression = false
   v8_enable_31bit_smis_on_64bit_arch = false
 
   # Sets -dOBJECT_PRINT.
@@ -235,11 +235,6 @@ if (v8_enable_fast_torque == "") {
   v8_enable_fast_torque = v8_enable_fast_mksnapshot
 }
 
-if (v8_enable_pointer_compression == "") {
-  # TODO(v8:v7703): temporarily enable pointer compression on x64
-  v8_enable_pointer_compression = v8_current_cpu == "x64"
-}
-
 assert(v8_current_cpu != "x86" || !v8_untrusted_code_mitigations,
        "Untrusted code mitigations are unsupported on ia32")
 

infra/mb/mb_config.pyl

@@ -457,10 +457,7 @@
       'release_bot', 'x64', 'minimal_symbols'],
     'release_x64_pointer_compression': [
       'release_bot', 'x64', 'dcheck_always_on', 'v8_enable_slow_dchecks',
-      # TODO(v8:v7703): Make pointer compression bots testing non pointer
-      # compression mode while pointer compression is temporarily enabled
-      # on x64
-      'v8_disable_pointer_compression'],
+      'v8_enable_pointer_compression'],
     'release_x64_trybot': [
       'release_trybot', 'x64'],
     'release_x64_test_features_trybot': [
@@ -816,10 +813,6 @@
       'gn_args': 'v8_enable_pointer_compression=true',
     },
 
-    'v8_disable_pointer_compression': {
-      'gn_args': 'v8_enable_pointer_compression=false',
-    },
-
     'v8_enable_test_features': {
       'gn_args': 'v8_enable_test_features=true',
     },