MacOS 11.2 refuses to set "no access" permissions on memory that
we previously used for JIT-compiled code. It is still unclear
whether this is WAI on the part of the kernel. In the meantime,
as a workaround, we use madvise(..., MADV_FREE_REUSABLE) instead
of mprotect(..., NONE) when discarding code pages. This is inspired
by what Chromium's gin platform does.

Fixed: v8:11389
Change-Id: I866586932573b4253002436ae5eee4e0411c45fc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2679688
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Auto-Submit: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72559}