This is a reland of commit c4301c04:
- Fix thin string in string-compare.js with low gc interval

Original change:
- Rename TryBuildCompareOperationBranch to TryBuildCompareOperation
- Add CheckedInternalizedString conversion Node that checks for string
  inputs and extracts internalised Strings from ThinStrings
- Add BranchIfReferenceCompare Node
- Add runtime functions to create internalised and thin Strings
- Add deopt check to test/mjsunit/maglev/int32-branch.js

Bug: v8:7700
Change-Id: I9221253f6bbeef12297419495c6eaf5096e06278
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3755152Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81680}