Handling of `std::tan` and `-ffast-math` on more recent versions of LLVM

[nkoukpaizan]

We are hitting an error in GridKit when attempting to differentiate std::tan with clang 19+ and -ffast-math. This works for clang 15 to clang 18.

Current workarounds include:

• Removing the -ffast-math flag, which may limit performance
• Adding a -fno-builtin-tan flag
• Rewriting the std::tan call explicitly as std::sin/std::cos

I would rather natively supporting this on the Enzyme side.

Here's an Enzyme explorer reproducer

cc @pelesh @wsmoses @lukelowry

[nkoukpaizan]

If I'm not mistaken, the fix would be to mark

Enzyme/enzyme/Enzyme/TypeAnalysis/TypeAnalysis.cpp

Line 104 in 5525eba

{"tan", Intrinsic::not_intrinsic},

as {"tan", Intrinsic::tan} #if LLVM_VERSION_MAJOR >= 19