[llvm] [SPARC] Preserve liveins after leaf register remapping (PR #213359)

[Kirill A. Korinsky via llvm-commits]

catap wrote:

@brad0 it can go first, but it needs to resolve some conflicts, and resolution of conflicts will introduce conflicts in cee7b71929312666c5cf48eb79873893811b99a7

:)

I can make here two commits or just rebase this be merged first and after prepare revert cee7b71929312666c5cf48eb79873893811b99a7 on top of this PR.

https://github.com/llvm/llvm-project/pull/213359