[DXIL] Add tan intrinsic part 2 (#90277)
This change is an implementation of #87367's investigation on supporting
IEEE math operations as intrinsics.
Which was discussed in this RFC:
https://discourse.llvm.org/t/rfc-all-the-math-intrinsics/78294
If you want an overarching view of how this will all connect see:
https://github.com/llvm/llvm-project/pull/90088
Changes:
- `llvm/include/llvm/IR/Intrinsics.td` - Create the tan intrinsic
- `llvm/lib/Target/DirectX/DXIL.td` - Map `int_tan` (the tan intrinsic)
to the equivalent DXIL Op.
