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

[Farzon Lotfi via cfe-commits]

farzonl wrote:

> I'm worried if we add a whole new series of math intrinsics without adding the corresponding constrained intrinsics, it's going to be confusing for anyone trying to understand how math intrinsics work. Why does tan exist, but not constrained tan?
> 
> `tan` is defined basically the same way as `sin` in Builtins.td; the only difference is that instead of `def SinF16F128 : Builtin, F16F128MathTemplate`, there's just `def TanF128 : Builtin {` (so no f16 support).

@efriedma-quic Would you be open to me making a new issue to support constrained intrinsics. I'll need to spend some time to see what's required to support them and I didn't want the current set of changes to go stale. 

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