This reverts commit 4d8e1846.

Reason for revert: Blocks V8 roll, crbug.com/1316800

Original change's description:
> [rwx][mac] Introduce RwxMemoryWriteScope
>
> ... as a single bottleneck that encapsulates the semantics and
> implementation of fast per-thread W^X permission switching supported
> by Apple Silicon (arm64 M1).
> On other architectures this class is a no-op.
>
> Bug: v8:12797
> Change-Id: Ica842ff9f843e20b7f61fd7e80591e7a1fd29771
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3586986
> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
> Commit-Queue: Igor Sheludko <ishell@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#79994}

Bug: v8:12797
Change-Id: I81792567839e72b4147d009c0845b0c0de003eb0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3590752
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Deepti Gandluri <gdeepti@chromium.org>
Owners-Override: Deepti Gandluri <gdeepti@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80007}