[llvm] [Attributor] Check callback broker argument aliases correctly (PR #218672)

[Tomas Matheson via llvm-commits]

tommat01 wrote:

> LGTM, though I found the terminology in your PR description a bit confusing (I don't think I've seen "broker" used in the context of abstract call-sites before?)

Thanks. I might be using the term incorrectly, but I got it from here https://github.com/llvm/llvm-project/blob/main/llvm/include/llvm/IR/AbstractCallSite.h#L28-L45 and it's used in a few tests like clang/test/CodeGen/callback_annotated.c

https://github.com/llvm/llvm-project/pull/218672