[llvm] [LLVM] Change `Intrinsic::getBaseName` to return `std::string` (PR #111613)

[Rahul Joshi via llvm-commits]

jurahul wrote:

I split out the new LLVM C API that @nhaehnle proposed into a separate PR here: https://github.com/llvm/llvm-project/pull/112197

For compile time measurement, it seems I need to follow the steps in https://llvm-compile-time-tracker.com/ to get some compile time data here.

https://github.com/llvm/llvm-project/pull/111613