This CL adds shared spaces for regular and large objects in the shared
space isolate. Spaces aren't used for allocation yet.

Bug: v8:13267
Change-Id: If508144530f4c9a1b3c0567570165955b64cc200
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3876824Reviewed-by: Jakob Linke <jgruber@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#83178}