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

[Sander de Smalen via llvm-commits]

sdesmalen-arm wrote:

> I think in practice needsWinCFI will almost always be true on Windows; clang will add "uwtable" attributes.
> 
> In order to reduce the number of different configurations, I think I'd prefer to always use Windows-style prologue/epilogue lowering on Windows, even if it isn't strictly required.

Before I update the commit message, I just want to check that this is what you intended?

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