Revert "Reland "cppgc: Enable pointer compression by default on Desktop""

This reverts commit 4c8f742e.

Reason for revert: Looks like it causes another gpu bot failure, see
the reland commit.

Original change's description:
> Reland "cppgc: Enable pointer compression by default on Desktop"
>
> Now that the marking verifier doesn't verify stack, reenable PC.
>
> Bug: chromium:1325007
> Change-Id: I85c4ed0a76cf84992781966d3694211e8ea36a1d
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3785147
> Commit-Queue: Anton Bikineev <bikineev@chromium.org>
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#82001}

Bug: chromium:1325007
Change-Id: Ic19810cc2e3e67bd7691465ca5be7bf724501213
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3789501
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Auto-Submit: Anton Bikineev <bikineev@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82002}

BUILD.gn

@@ -834,12 +834,6 @@ if (cppgc_enable_caged_heap) {
 
   # Always enable young generation compile time flag if caged heap is enabled.
   cppgc_enable_young_generation = true
-
-  if (is_linux || is_mac || is_win) {
-    # Always enable on desktop but avoid on ChromeOS for now (for stability
-    # reasons).
-    cppgc_enable_pointer_compression = true
-  }
 }
 if (cppgc_enable_young_generation) {
   enabled_external_cppgc_defines += [ "CPPGC_YOUNG_GENERATION" ]