[clang] [CIR][AArch64] Port f64 tests for v8.5 rounding NEON builtins (PR #221389)

[Andrzej Warzyński via cfe-commits]

https://github.com/banach-space approved this pull request.

Great, thank you! LGTM % nit

Note to myself: this completes https://arm-software.github.io/acle/neon_intrinsics/advsimd.html#rounding-3 🥳 

Btw, @iamvickynguyen , would you be able to move the rounding tests from intrinsics.c to rounding.c? It will be much cleaner if we keep them in rounding.c + rounding-v8.5.c (as opposed to intrinsics.c + rounding-v8.5.c). Thank you!

https://github.com/llvm/llvm-project/pull/221389