This reverts commit 1f35c165.

Reason for revert: speculative revert for TSAN failure:
https://ci.chromium.org/p/v8/builders/ci/V8%20Linux64%20TSAN%20-%20concurrent%20marking/12179



Original change's description:
> [objects] Update JSArrayBuffer::extension-field in two steps
> 
> The JSArrayBuffer::extension-field might not be aligned with pointer
> compression enabled. However on AArch64 pointers need to be aligned if
> you perform atomic operations on them. Therefore split extension into
> two 32-bit words that each get updated atomically. There is no ABA
> problem here since the extension field only transitions from
> NULL --> value --> NULL. After Detach(), Attach() isn't invoked anymore.
> 
> Bug: v8:10064
> Change-Id: If987ed51f0528ca7313980f3d36ffca300b75fdc
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2071256
> Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#66457}

TBR=ulan@chromium.org,dinfuehr@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: v8:10064
Change-Id: I2107a4d49d2b127dc65ce11b3b61ccc592fb0736
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2078579Reviewed-by: Sathya Gunasekaran  <gsathya@chromium.org>
Reviewed-by: Tamer Tas <tmrts@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Sathya Gunasekaran  <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66485}