ScopeInfo will contain either inlined (array) local names or
a hash table (names => index) containing the local names.

We abstract iteration with LocalNameIterator and remove
ContextLocalName since accessing a local name by index in
the hash table would be expensive.

This CL only implements the iterator for the array.

Bug: v8:12315
Change-Id: I2c62802652fca1cf47815ce8768a3f7487f2c39f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3386603Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78623}