[clang] [llvm] [WebAssembly] Implement prototype f32.load_f16 instruction. (PR #90906)

[Brendan Dahl via llvm-commits]

brendandahl wrote:

> Overall this looks good, and I think it makes sense to model this as short* for now. I think it will be interesting to see if that ends up causing issues. Out of curiosity does this work if you try `_fp16`?

I was trying _Float16 and that wasn't working since it requires the target to support it. `__fp16` does work though. I'll change it.

https://github.com/llvm/llvm-project/pull/90906