[clang] [llvm] Reland "[InstCombine] Combine llvm.sin/llvm.cos libcall pairs into llvm.sincos" (PR #194616)

[Sushant Gokhale via cfe-commits]

sushgokh wrote:

@kito-cheng I think this is causing regression with SPEC17 526.blender/510.parest in `-flto -ffast-math` mode. The regression is around 2-2.5%. I will try to come up with a reproducer soon.

https://github.com/llvm/llvm-project/pull/194616