[clang] [clang][WebAssembly] Handle casted function pointers with different number of arguments (PR #153168)

[Jorge Zapata via cfe-commits]

turran wrote:

> Maybe a flag. But I'd prefer to explore the design space first. What patterns do we care about? Can we detect all the relevant cases at compile-time? Can we generalize this by performing some checks at runtime?

I added a couple of tests that highly represent the main set of use cases that this PR solves.  Using a cast for a function pointer struct field declaration, and when using a cast for call arguments.

About other potential relevant cases, I guess there might be more, but for my own scenario with the PR, it is enough.
Let me know if the design is reasonable for these cases

https://github.com/llvm/llvm-project/pull/153168