This CL extends BoundedPageAllocator with PageFreeingMode parameter
which controls how pages should be freed: by setting permissions to
kNoAccess (preferred) or by discarding pages (Apple Silicon specific
behavior for RWX pages). The latter mode allows to ensure that once
pages are configured with RWX permissions they are never reconfigured
to anything else again.

The new mode will be used in a follow-up CL.

Bug: v8:12797
Change-Id: I3277f56ea6fee9c9b38b1682e68c22e66e9a02a4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3606228Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80162}