This reverts commit af5f437c.

Reason for revert: Seems to break TSAN - https://ci.chromium.org/p/v8/builders/ci/V8%20Linux64%20TSAN/33286?

Original change's description:
> [heap] Fix tracking of code pages for V8 stack unwinder
> 
> When a compaction space allocates a new code page, that pages needs to
> be added to the Isolate::code_pages_ array used for stack unwinding.
> Since the array is owned by the main thread, compaction thread cannot
> directly modify it. Because of that code pages are added upon merging
> of the compaction space to the main spage in MergeLocalSpace.
> 
> The bug was that all code pages coming from the compaction space
> were added to the code_pages_ array. However, some of the pages are
> not newly allocated but merely borrowed from the main space.
> 
> This CL introduces a new page flag for marking pages that are borrowed
> during compaction and skips them in MergeLocalSpace.
> 
> Bug: v8:10900
> Change-Id: I786dc5747bd7c785ae58dfd8b841c00774efb15e
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2416500
> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
> Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
> Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#69992}

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

Change-Id: I13f8b64014750af95423166152dc9bee8cec12d0
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:10900
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2418395Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69993}