[llvm] [AArch64] Refactor allocation of locals and stack realignment (PR #72028)

[Sander de Smalen via llvm-commits]

https://github.com/sdesmalen-arm approved this pull request.

The refactoring of FrameLowering code looks good to me. Just one very small nit on one of the tests.

https://github.com/llvm/llvm-project/pull/72028