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

This reverts commit d471ec9f.

Reason for revert: Unexpected redness on non-ptr-compr bots.

Original change's description:
> [ptr-compr][x64] Temporarily enable pointer compression on x64
>
> Bug: v8:7703
> Change-Id: Id7858d2d7324670d01836f7acbb952cd99c4a8b7
> 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/+/1849522
> Commit-Queue: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Toon Verwaest <verwaest@chromium.org>
> Reviewed-by: Michael Achenbach <machenbach@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#64248}

Tbr: verwaest@chromium.org,machenbach@chromium.org
No-Tree-Checks: true
Bug: v8:7703
Change-Id: I841d9722642f75f1277aedd70c4476aee041d946
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1857218Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64251}

BUILD.gn

@@ -203,9 +203,8 @@ declare_args() {
 }
 
 if (v8_enable_pointer_compression == "") {
-  # TODO(v8:v7703): temporarily enable pointer compression on arm64 and on x64
-  v8_enable_pointer_compression =
-      v8_current_cpu == "arm64" || v8_current_cpu == "x64"
+  # TODO(v8:v7703): temporarily enable pointer compression on arm64
+  v8_enable_pointer_compression = v8_current_cpu == "arm64"
 }
 
 # Toggle pointer compression for correctness fuzzing when building the

infra/mb/mb_config.pyl

@@ -455,9 +455,9 @@
       'release_bot', 'x64', 'minimal_symbols'],
     'release_x64_pointer_compression': [
       'release_bot', 'x64', 'dcheck_always_on', 'v8_enable_slow_dchecks',
-      'v8_disable_pointer_compression'],
+      'v8_enable_pointer_compression'],
     'release_x64_pointer_compression_without_dchecks': [
-      'release_bot', 'x64', 'v8_disable_pointer_compression'],
+      'release_bot', 'x64', 'v8_enable_pointer_compression'],
     'release_x64_trybot': [
       'release_trybot', 'x64'],
     'release_x64_test_features_trybot': [
@@ -788,6 +788,10 @@
       'gn_args': 'v8_enable_slow_dchecks=true',
     },
 
+    'v8_enable_pointer_compression': {
+      'gn_args': 'v8_enable_pointer_compression=true',
+    },
+
     'v8_disable_pointer_compression': {
       'gn_args': 'v8_enable_pointer_compression=false',
     },