[clang] [Clang][Sema] Fix crash when __funcref is applied to non-function-poi… (PR #176102)

[Paulo Matos via cfe-commits]

pmatos wrote:

Not completely sure we should run these tests for wasm64 as well with:
```
// RUN: %clang_cc1 -fsyntax-only -verify -triple wasm64 -target-feature +reference-types %s
```

but I think it should be fine as is since wasm32/64 doesn't matter too much.

https://github.com/llvm/llvm-project/pull/176102