This reverts commit 31c66193.

Reason for revert: Speculative revert for lots of timeouts on the
tree, some seem heap related, e.g.
https://ci.chromium.org/p/v8/builders/ci/V8%20Linux64%20-%20cfi/25151

Original change's description:
> [heap] Expand new space in safepoint
> 
> Move expansion of the new space into the safepoint. Otherwise background
> threads race with the main thread when accessing the new space capacity.
> This will most likely also be required to allow the allocation of new
> space objects from background threads.
> 
> Bug: v8:10315
> Change-Id: Ia8ac0c9f582876b655eaf4e35082aeadfbdb830e
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2235532
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#68226}

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

Change-Id: I8da9aa000090a9bff43bb15b7bb55bb5a3138fe5
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:10315
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2235539Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68237}