This reverts commit ed3636e2.

Reason for revert: Seems to lead to several timeouts in debug mode:
https://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20debug/builds/19780

And on windows.

Original change's description:
> [heap] Ensure that OOM callback is called before OOM.
> 
> This patch also fixes MaxReserved() to accound for page headers and
> adds two tests for heap size and memory allocator size near OOM.
> 
> Bug: chromium:824214
> Change-Id: I5bbe00a9d6a5798cdf4481861a10dca842244a63
> Reviewed-on: https://chromium-review.googlesource.com/973614
> Reviewed-by: Hannes Payer <hpayer@chromium.org>
> Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#52184}

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

Change-Id: I1a98c070cee4039a1ef7851fcabd32d56d0629fe
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:824214
Reviewed-on: https://chromium-review.googlesource.com/977973Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52192}