Remove llvm-muladd pass and move it's functionality to to llvm-simdloop (#55802)
Closes https://github.com/JuliaLang/julia/issues/55785
I'm not sure if we want to backport this like this. Because that removes
some functionality (the pass itself). So LLVM.jl and friends might need
annoying version code. We can maybe keep the code there and just not run
the pass in a backport.