[llvm] [AArch64] Use Windows-style prologue/epilogue regardless of CFI. (PR #156467)

[Eli Friedman via llvm-commits]

efriedma-quic wrote:

I've never heard of anything requiring that the frame record is 16-byte aligned.  AAPCS64 and the relevant Microsoft documentation say nothing.

I think the frame record ending up misaligned was an accident, though.  https://learn.microsoft.com/en-us/cpp/build/arm64-exception-handling says the frame record should be on the other side of the integer register spills.

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