[clang] Add _MM_FROUND_TIES_TO_EVEN to avx512fintrin.h (PR #99691)

[Phoebe Wang via cfe-commits]

phoebewang wrote:

Thanks @hpkfft for the thorough explanation. I'm fine with either `_MM_FROUND_TIES_TO_EVEN` or `_MM_FROUND_TO_NEAREST_TIES_EVEN`. Let's see GCC community preference.

https://github.com/llvm/llvm-project/pull/99691