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

[Derek Schuff via cfe-commits]

https://github.com/dschuff approved this pull request.

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`?

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