[llvm] Add support for ref.func to AsmParser/MC (PR #163326)

[Demetrius Kanios via llvm-commits]

QuantumSegfault wrote:

I figured as much. That's the way it would have to been have done before "reference-types". 

However `ref.func` is most direct way to accomplish what I want in WASM, and was able to easily make use of it with Binaryen. Now I'm trying to use the same direct approach with LLVM.

----

I'm leaning towards `addrspacecast` for the IR-level lowering.

https://github.com/llvm/llvm-project/pull/163326