[llvm] [NFC] Add GIntrinsic::setIntrinsicID (PR #106236)

[Rahul Joshi via llvm-commits]

jurahul wrote:

Makes sense. I was referring to `MachineInstr::removeOperand` for example, which is a public function in the parent class. In my use case (in downstream code) the mutation I want to do is in a MachineFunctionPass, so not sure if the GISel combiner helper is relevant there. I guess in that context, the question is where mutation is ok and allowed. Of course safety if the mutation has to be ensured by the mutator. And if mutation is ok, are such helpers ok as well.

A second related question here, more process wise, is how to make such changes with no upstream users. I am suspecting the answer is we cannot unless the pass using this is also upstream.

https://github.com/llvm/llvm-project/pull/106236