The page size of PPC is kept unchanged because PPC has larger
physical pages (64KB).

Bug: chromium:852420

Change-Id: Ib888ea00a476ff103e00211dbb439186148ef81e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1481631
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#60296}