When a reservation of exactly 4GB is requested on a 32-bit platform,
we can simply pretend that we tried and failed.

Fixed: chromium:1107234
Change-Id: I9a3f4dbd31064aff620337aa291768fe47174fb4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2308346
Auto-Submit: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68968}