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

[Sander de Smalen via llvm-commits]

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

Some minor nits, but otherwise LGTM.

Could you also please update the PR's title and commit message, to reflect the new name before committing?

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