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

[Phoebe Wang via cfe-commits]

phoebewang wrote:

I'm good with adding the macro. But how it propagates to other compilers would be an chicken or the egg problem. User won't use this flag if they care the portability, while other compilers may be reluctant to add it if no requiest from their user.

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