[clang] [CIR][Aarch64] upstream scalar & vector intrinsics (FP16) (PR #190310)

[Rafe Murray via cfe-commits]

rafe-murray wrote:

@banach-space thanks for the ping! Unfortunately I've been really busy with work recently and haven't had time to work on this. Hopefully over the next week or two I can get a PR up. I'm also open to splitting the work with someone else as I understand this has been a while.

https://github.com/llvm/llvm-project/pull/190310