A lot of the space/chunk methods can be trivially marked as const.

There are more methods that can be made const but these will require
creating new const object iterators, so those are left out for now.

Bug: v8:12612
Change-Id: I753b8b3f7a200ecf255596c7825917e4eb600b81
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3571815Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79824}