[llvm] [Draft] Support save/restore point splitting in shrink-wrap (PR #119359)

[Elizaveta Noskova via llvm-commits]

enoskova-sc wrote:

I've rebased my patches against a relatively recent LLVM version. While the patches aren’t perfect yet, I’ve made an effort to ensure all tests pass. As a next step, I plan to split this merge request into smaller parts and prepare the next patch in a separate MR for easier review.

https://github.com/llvm/llvm-project/pull/119359