[llvm] [AArch64] Fix SVE callee-save layout for nounwind functions on Windows (PR #156467)

[Eli Friedman via llvm-commits]

https://github.com/efriedma-quic commented:

Maybe should use `MF.getTarget().getMCAsmInfo()->usesWindowsCFI()` to check for "Windows" in this context, though.  UEFI targets use Windows unwind, but technically aren't Windows.

https://github.com/llvm/llvm-project/pull/156467