[llvm] [aarch64] atan2 intrinsic lowering (p5) (PR #112611)

[Tex Riddell via llvm-commits]

tex3d wrote:

@tschuett 
> Known Windows issue: #112961

Thanks, I rebased, so hopefully those pipelines will pass now.  If the change looks good to you, would you like to approve?

https://github.com/llvm/llvm-project/pull/112611