use registered ModuleLoader instead of hardcoding P6::ML
use registered ModuleLoader instead of hardcoding P6::ML

When parsing we invoked P6::ML before, and at runtime the registered one.
Now it is consistant and lets us register a custom ML.

sjn/rakudo,retupmoca/rakudo,lucasbuchala/rakudo,usev6/rakudo,zostay/rakudo,tony-o/rakudo,sjn/rakudo,paultcochrane/rakudo,tony-o/rakudo,LLFourn/rakudo,softmoth/rakudo,azawawi/rakudo,tony-o/rakudo,nbrown/rakudo,tony-o/deb-rakudodaily,retupmoca/rakudo,Leont/rakudo,dankogai/rakudo,b2gills/rakudo,Gnouc/rakudo,tbrowder/rakudo,salortiz/rakudo,awwaiid/rakudo,sergot/rakudo,b2gills/rakudo,ungrim97/rakudo,MasterDuke17/rakudo,dwarring/rakudo,dankogai/rakudo,MasterDuke17/rakudo,labster/rakudo,lucasbuchala/rakudo,sjn/rakudo,nbrown/rakudo,skids/rakudo,MasterDuke17/rakudo,Leont/rakudo,lucasbuchala/rakudo,usev6/rakudo,laben/rakudo,b2gills/rakudo,dwarring/rakudo,awwaiid/rakudo,Gnouc/rakudo,raydiak/rakudo,ungrim97/rakudo,zhuomingliang/rakudo,ugexe/rakudo,softmoth/rakudo,samcv/rakudo,retupmoca/rakudo,niner/rakudo,jonathanstowe/rakudo,teodozjan/rakudo,jonathanstowe/rakudo,softmoth/rakudo,niner/rakudo,tbrowder/rakudo,raydiak/rakudo,zhuomingliang/rakudo,LLFourn/rakudo,zostay/rakudo,rakudo/rakudo,tbrowder/rakudo,awwaiid/rakudo,tony-o/deb-rakudodaily,laben/rakudo,MasterDuke17/rakudo,softmoth/rakudo,cognominal/rakudo,tbrowder/rakudo,tony-o/deb-rakudodaily,awwaiid/rakudo,salortiz/rakudo,jonathanstowe/rakudo,labster/rakudo,samcv/rakudo,paultcochrane/rakudo,LLFourn/rakudo,azawawi/rakudo,softmoth/rakudo,dankogai/rakudo,tony-o/deb-rakudodaily,azawawi/rakudo,teodozjan/rakudo,salortiz/rakudo,Gnouc/rakudo,teodozjan/rakudo,salortiz/rakudo,cygx/rakudo,rakudo/rakudo,cygx/rakudo,nunorc/rakudo,zhuomingliang/rakudo,samcv/rakudo,sergot/rakudo,ab5tract/rakudo,paultcochrane/rakudo,cognominal/rakudo,ungrim97/rakudo,ugexe/rakudo,tony-o/deb-rakudodaily,nunorc/rakudo,laben/rakudo,tony-o/rakudo,ugexe/rakudo,ab5tract/rakudo,jonathanstowe/rakudo,zhuomingliang/rakudo,rakudo/rakudo,skids/rakudo,jonathanstowe/rakudo,nunorc/rakudo,LLFourn/rakudo,nunorc/rakudo,usev6/rakudo,samcv/rakudo,raydiak/rakudo,paultcochrane/rakudo,cygx/rakudo,Leont/rakudo,nbrown/rakudo,ab5tract/rakudo,dankogai/rakudo,retupmoca/rakudo,MasterDuke17/rakudo,rakudo/rakudo,ungrim97/rakudo,ugexe/rakudo,tbrowder/rakudo,paultcochrane/rakudo,Gnouc/rakudo,azawawi/rakudo,sjn/rakudo,labster/rakudo,skids/rakudo,rakudo/rakudo,lucasbuchala/rakudo,awwaiid/rakudo,b2gills/rakudo,nbrown/rakudo,rakudo/rakudo,cognominal/rakudo,niner/rakudo,labster/rakudo,tony-o/rakudo,zostay/rakudo,skids/rakudo,ungrim97/rakudo,ab5tract/rakudo,dankogai/rakudo,ugexe/rakudo,sergot/rakudo,tony-o/rakudo,raydiak/rakudo,cognominal/rakudo,tbrowder/rakudo,ab5tract/rakudo,labster/rakudo,salortiz/rakudo,MasterDuke17/rakudo,usev6/rakudo,samcv/rakudo,sergot/rakudo,zostay/rakudo,dwarring/rakudo,LLFourn/rakudo,cognominal/rakudo,laben/rakudo,labster/rakudo,Gnouc/rakudo,nbrown/rakudo,azawawi/rakudo,cygx/rakudo,tony-o/deb-rakudodaily,teodozjan/rakudo,Leont/rakudo,b2gills/rakudo,dwarring/rakudo,niner/rakudo,salortiz/rakudo,lucasbuchala/rakudo,Gnouc/rakudo,skids/rakudo,tony-o/deb-rakudodaily,nbrown/rakudo,sjn/rakudo,usev6/rakudo,cygx/rakudo