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

This reverts commit 111d20bb.

Reason for revert:
- crashes
- flaky test failures
- ubsan errors
- Speedometer regression

Original change's description:
> Reland "cppgc: Enable pointer compression by default on Desktop"
>
> Reland since ubsan failures were fixed.
>
> Original change's description:
> > Revert "cppgc: Enable pointer compression by default on Desktop"
> >
> > This reverts commit 4cf08c1a.
> >
> > Reason for revert: broke ubsan.
> >
> > Original change's description:
> > > cppgc: Enable pointer compression by default on Desktop
> > >
> > > The CL enables pointer compression in Oilpan.
> > >
> > > For sherrifs: the CL may cause some slight perf regressions (likely
> > > blink_perf.*), due to slightly higher cost of compression and
> > > decomrpession.
> > >
> > > Speedometer2 is not expected to regress, as was checked locally. Such a
> > > slight performance degradation is compensated by memory savings that are
> > > expected to be around 10-20% of Oilpan committed size (~2.5-5% of Renderer
> > > PMF).
> > >
> > > Bug: chromium:1325007
> > > Change-Id: I2e31fc56250dbe6354a7614fa1f9e926260d842b
> > > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3695565
> > > Commit-Queue: Anton Bikineev <bikineev@chromium.org>
> > > Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> > > Cr-Commit-Position: refs/heads/main@{#81442}
> >
> > Bug: chromium:1325007
> > Change-Id: Iabc31ed683841ba0189dee9028da330dc03d7e09
> > No-Presubmit: true
> > No-Tree-Checks: true
> > No-Try: true
> > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3735168
> > Auto-Submit: Anton Bikineev <bikineev@chromium.org>
> > Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
> > Commit-Queue: Anton Bikineev <bikineev@chromium.org>
> > Cr-Commit-Position: refs/heads/main@{#81443}
>
> Bug: chromium:1325007
> Change-Id: Ifc8ea0e73e99d9be622e27d3d4c79d0e35fd459c
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3735128
> Commit-Queue: Anton Bikineev <bikineev@chromium.org>
> Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
> Cr-Commit-Position: refs/heads/main@{#81486}

Bug: chromium:1325007
Change-Id: I35d9085b9c39fd212002f098a3a015d0db7504a0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3743468
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81516}

BUILD.gn

@@ -812,12 +812,6 @@ 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" ]