[llvm] [WebAssembly] Lower fmuladd to fma (PR #161355)

[Sam Parker via llvm-commits]

sparker-arm wrote:

The pattern matching confused me yesterday and, after looking with fresh eyes, I'm pretty sure that's because the operands were ordered incorrectly in the original patterns. AFAICT the wasm instructions and ISD nodes both use the same operand order for FMA. @badumbatish Could you please take a look and confirm? 

https://github.com/llvm/llvm-project/pull/161355