[llvm] [AArch64][SME2] Add FORM_STRIDED_TUPLE pseudo nodes (PR #116399)

[Sander de Smalen via llvm-commits]

https://github.com/sdesmalen-arm commented:

This PR doesn't make much sense without seeing the accompanying PR that improves the register allocation using these nodes. Could you either fold those changes into this PR, or stack another PR on top of this one?

https://github.com/llvm/llvm-project/pull/116399