Initialize the (thread-local) memory protection key permissions for any
isolate that joins the wasm engine. Otherwise it can happen that an
isolate gets Wasm code from the cache without ever compiling anything
(hence without ever changing memory protection key permissions), and
then it would not be allowed to access (read or execute) the code.

I tested this change manually on a PKU-enabled devices. The new test
crashed before the fix, and completes successfully afterwards.

R=ahaas@chromium.org

Bug: v8:11974, chromium:1280451
Change-Id: I90dded8b4fdaa8cf34b44107291d3f525ce16335
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3347563Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78413}