[llvm] [PowerPC] Mark llvm.tan on vectors as expand (PR #95507)

[Farzon Lotfi via llvm-commits]

farzonl wrote:

Hi thanks for picking this up iI've been working on a general fix so I have a list of all the tests that need to be updated. For PowerPC it is:

- CodeGen/PowerPC/f128-arith.ll
- CodeGen/PowerPC/lower-intrinsics-afn-mass.ll
- CodeGen/PowerPC/lower-intrinsics-afn-mass_notail.ll
- CodeGen/PowerPC/lower-intrinsics-fast-mass.ll
- CodeGen/PowerPC/lower-intrinsics-fast-mass_notail.ll
- CodeGen/PowerPC/lower-intrinsics-nofast-mass.ll
- CodeGen/PowerPC/unal-altivec2.ll
- CodeGen/PowerPC/lower-intrinsics-fast-mass.ll
- CodeGen/PowerPC/lower-intrinsics-fast-mass_notail.ll
- CodeGen/PowerPC/lower-intrinsics-nofast-mass.ll
- CodeGen/PowerPC/unal-altivec2.ll

Also in `llvm/include/llvm/Analysis/VecFuncs.def  add
```cpp
TLI_DEFINE_VECFUNC("llvm.tan.f64", "__tand2", FIXED(2), "_ZGV_LLVM_N2v") 
TLI_DEFINE_VECFUNC("llvm.tan.f32", "__tanf4", FIXED(4), "_ZGV_LLVM_N4v")
```

https://github.com/llvm/llvm-project/pull/95507