AIX: Update code alignment to 64-bytes

Code alignment was updated to 64-bytes on ppc:
https://crrev.com/c/3528993

This change is required to maintain the same alignment on AIX.

Change-Id: I8cc33c9abad1ceeac050fde30700d315ef549d7f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3552087


Reviewed-by: Vasili Skurydzin <vasili.skurydzin@ibm.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Milad Farazmand <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/main@{#79639}