[llvm] [C API] Fix LLVMGetOrdering/LLVMIsAtomicSingleThread for fence/memory instrs (PR #65228)

[Benji Smith via llvm-commits]

Benjins wrote:

Is that something you can do, or should I reach out to someone else? I don't have access rights to merge it

https://github.com/llvm/llvm-project/pull/65228