This reverts commit 8218c061.

Reason for revert: compile failures, e.g.:
https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Mac%20-%20arm64%20-%20release%20builder/11040/overview

Original change's description:
> [wasm] Reset PKRU before spawning new threads
>
> We sometimes hit the DCHECK in the wasm code manager:
>   DCHECK_IMPLIES(writable, !MemoryProtectionKeyWritable());
>
> This is because we spawn new threads while having a
> {CodeSpaceWriteScope} open. In the case of PKU, this changes the PKRU
> register to allow writes to the code space, and the value of that
> register is inherited by any new thread. If this thread then tries to
> switch to writable code spaces, it hits the DCHECK. It would hit a
> similar DCHECK when trying to execute code.
>
> We fix this issue by temporarily resetting the PKRU register to
> non-writable while we call the {NotifyConcurrencyIncrease} method. This
> is not a very robust solution, as any new call that potentially happens
> inside a {CodeSpaceWriteScope} needs to do the same, but refactoring the
> code to avoid spawning new threads while being in writable state would
> be a lot of work with other downsides.
>
> R=​jkummerow@chromium.org
>
> Bug: v8:13075
> Change-Id: Ibc7270aa597902dc6d9649cb6bcdfce8b1a9bafc
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3762579
> Commit-Queue: Clemens Backes <clemensb@chromium.org>
> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#81729}

Bug: v8:13075
Change-Id: I235e7263856a37cf0f4aa1c27493aac8e6db7910
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3763587
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Auto-Submit: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81730}