[clang] [llvm] [clang] Reland Add tanf16 builtin and support for tan constrained intrinsic (PR #94559)

[Farzon Lotfi via llvm-commits]

farzonl wrote:

> Should a test be added when the return type is a different float type than the first arg type?

So  if our function that calls the builtin has a different return type than the input that we pass in to the builtin then that will be handled by other casting code that has its own tests so no.

Second way this could happen if tan had different return type than from input type but in this case input dictates return type for tan.  So the answer again would be no.

https://github.com/llvm/llvm-project/pull/94559