[clang] [CLANG] Full support of complex multiplication and division. (PR #81514)

[Zahira Ammarguellat via cfe-commits]

zahiraam wrote:

This is still WIP in progress, but I would like to get @MaskRay's opinion about the feasibility of getting this new option approved knowing that the 2 options being potentially replaced are already merged in clang18 and are probably already used by some users.

https://github.com/llvm/llvm-project/pull/81514