The function assumes that the area of a page after the high watermark
is not in the free list. This does not hold if allocation observer are
active during deserialization.

Change-Id: I1f8d0586be6dc535e85d9da5b0fb2791f1de1031
Reviewed-on: https://chromium-review.googlesource.com/829573Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50132}