This reverts commit d3a72e3c.

Reason for revert: MSAN failures (https://ci.chromium.org/p/v8/builders/ci/V8%20Linux%20-%20arm64%20-%20sim%20-%20MSAN/32360)

Original change's description:
> cppgc: Stack scanning using ObjectStartBitmap
> 
> This CL implements stack scanning for cppgc.
> Given a value on the stack, the MarkingVisitor uses
> PageBackend::Lookup to checks whether that address is on
> the heap. If it is, BasePage::TryObjectHeaderFromInnerAddress
> (introduced in this CL) is used to get the relevant object
> header. Note that random addresses on the heap might point to
> free memory, object-start-bitmap, etc.
> 
> If a valid object header is found:
> * If the object is not in construction, the GCInfoIndex is used
> the get the relevant Trace method and the object is traced.
> * Otherwise, the object is conservatively scanned - i.e. the
> payload of the object is iterated word by word and each word is
> treated as a possible pointer.
> 
> Only addresses pointing to the payload on non-free objects are
> traced.
> 
> BasePage::TryObjectHeaderFromInnerAddress assumes on LAB on the
> relevant space, thus all LABs are reset before scanning the stack.
> 
> Bug: chromium:1056170
> Change-Id: I172850f6f1bbb6f0efca8e44ad8fdfe222977b9f
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2190426
> Commit-Queue: Omer Katz <omerkatz@chromium.org>
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Reviewed-by: Anton Bikineev <bikineev@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#67795}

TBR=ulan@chromium.org,mlippautz@chromium.org,bikineev@chromium.org,omerkatz@chromium.org

Change-Id: I3caef6f9f55911fd1a86e895c3495d1b98b1eac2
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:1056170
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2201136Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67796}