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

[Robin Charles Gilbert via cfe-commits]

robincharlesgilbert wrote:

> Aren't the latest versions of Intel's compiler, `icx`, based on LLVM?

Correct. However, the libraries (e.g. math libraries) were all ported from `icl` to `icx`. Getting the math libraries of `icl` to compile with `icx` was among the last things I did for the company.

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