For prototype loads from strings, we require an access check, since
string maps are shared between native contexts. This makes our prototype
constant load optimisation bail out to a generic load.

We can, however skip this check given the knowledge that this is a
prototype load from a primitive, and instead emit a string check. We can
also be a slight bit more tolerant of multiple different string maps,
same as TF.

Bug: v8:7700
Change-Id: I4ad858cadea68246f903443d19fa6cdd65a14564
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3762576Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81751}