[clang] [llvm] [AArch64] Stack probing for function prologues (PR #66524)

[Momchil Velikov via cfe-commits]

momchil-velikov wrote:

I'm going to squash the commits which belong to this PR as I don't believe they are useful in isolation anymore and they get in the way of refactoring/rebasing.

 (Long story short, I did a patch to avoid having two back to back probing loops, then factored out a stack probing independent part (to come in a separate review later)  and rebasing this PR on top of it is a major pain).


https://github.com/llvm/llvm-project/pull/66524