This reverts commit 099b1cf3.

Reason for revert: Fails on MSAN - https://ci.chromium.org/p/v8/builders/ci/V8%20Clusterfuzz%20Linux%20MSAN%20no%20origins/16034?

Original change's description:
> [heap] Introduce fast path in PagedSpace::AllocateRaw
> 
> Introduce explicit fast path for allocation in PagedSpace. The slow path
> is moved into AllocateRawSlow which refills the LAB and retries the
> allocation.
> 
> Bug: v8:10315
> Change-Id: I807e56ccde833b0e9a42166b4883c1978d01e828
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2277808
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#68653}

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

Change-Id: I11ce25da69a24a0a5ccc5e0324d1dfe71cdeaca0
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:10315
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2275969Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68654}