[llvm] InferAddressSpaces: Handle llvm.fake.use (PR #109567)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> Although `llvm.fake.use` is variadic, it's actually an error to have more than one argument (not enforced in the verifier, I'll add a patch for that) 

I do not think this is a reasonable restriction to have. It adds a new constraint any IR pass has to consider. Any of the many flavors of CSE would need to deal with it, for example. If this wants to be a minimally intrusive intrinsic, it needs to have as few constraints as possible 

https://github.com/llvm/llvm-project/pull/109567