[clang] [WebAssembly] Enable multivalue and reference-types in generic CPU config (PR #80923)

[Sam Clegg via cfe-commits]

sbc100 wrote:

After this lands does that mean that all object files will have `multi-value` in the features section?  Or only object files that actually use `mutli-value`?    

https://github.com/llvm/llvm-project/pull/80923