[clang] [CIR] Fold ComplexRealOp from ComplexCreateOp (PR #147592)

[Amr Hesham via cfe-commits]

AmrDeveloper wrote:

> We just went through a similar one with vector (in which the folding to constant vector (from a splat op) can actually increase code size)

Yes, I think for the current fold it has no side effect on size, it will eleminate one Inst, because that i added it to the folder not simplify

https://github.com/llvm/llvm-project/pull/147592