[clang] [clang] [Headers] Don't use unreserved name in avx512fp16intrin.h (PR #98478)

[Martin Storsjö via cfe-commits]

mstorsjo wrote:

> The only other unreserved name I could find in the file is:
> 
> https://github.com/llvm/llvm-project/blob/d9c26b9d560f4362503b8f0ec97a52a0a36a57ce/clang/lib/Headers/avx512fp16intrin.h#L99
> 
> (uses `h`)
> so we might as well fix this at the same time. We should probably have tests using https://clang.llvm.org/extra/clang-tidy/checks/bugprone/reserved-identifier.html that runs over all of the system headers we produce to issue a diagnostic when we use an unreserved identifier so that we catch this issue more explicitly.

We seem to have gotten more cases of such unreserved identifiers in 83ad644afaac23577e3563d3ec1fac1b1fde37f4 (see the fallout of it in #161736), so I think it's somewhat urgent to set up such automated testing of the Clang headers.

https://github.com/llvm/llvm-project/pull/98478