[clang] [llvm] [clang][hlsl] Add tan intrinsic part 1 (PR #90276)

[Eli Friedman via cfe-commits]

https://github.com/efriedma-quic approved this pull request.

Okay.  I mostly just want to make sure the plan isn't "land all the intrinsics from the RFC, then eventually investigate the constrained intrinsics".

LGTM

https://github.com/llvm/llvm-project/pull/90276