Streamline multidim array slicing
Streamline multidim array slicing

- postfixize loops
- fail fast to slow path as soon as non-Int seen, instead of setting flag

tony-o/rakudo,b2gills/rakudo,labster/rakudo,tony-o/rakudo,Gnouc/rakudo,sjn/rakudo,b2gills/rakudo,raydiak/rakudo,sjn/rakudo,awwaiid/rakudo,sjn/rakudo,softmoth/rakudo,lucasbuchala/rakudo,lucasbuchala/rakudo,usev6/rakudo,usev6/rakudo,lucasbuchala/rakudo,raydiak/rakudo,Gnouc/rakudo,tbrowder/rakudo,tbrowder/rakudo,tbrowder/rakudo,raydiak/rakudo,awwaiid/rakudo,jonathanstowe/rakudo,jonathanstowe/rakudo,b2gills/rakudo,b2gills/rakudo,Gnouc/rakudo,samcv/rakudo,Gnouc/rakudo,sjn/rakudo,labster/rakudo,lucasbuchala/rakudo,lucasbuchala/rakudo,awwaiid/rakudo,labster/rakudo,tony-o/rakudo,rakudo/rakudo,zostay/rakudo,softmoth/rakudo,rakudo/rakudo,salortiz/rakudo,nbrown/rakudo,samcv/rakudo,tbrowder/rakudo,salortiz/rakudo,jonathanstowe/rakudo,MasterDuke17/rakudo,salortiz/rakudo,MasterDuke17/rakudo,samcv/rakudo,tony-o/rakudo,salortiz/rakudo,usev6/rakudo,zostay/rakudo,tony-o/rakudo,nbrown/rakudo,MasterDuke17/rakudo,nbrown/rakudo,Gnouc/rakudo,samcv/rakudo,usev6/rakudo,labster/rakudo,labster/rakudo,awwaiid/rakudo,tbrowder/rakudo,rakudo/rakudo,sjn/rakudo,softmoth/rakudo,tbrowder/rakudo,MasterDuke17/rakudo,softmoth/rakudo,rakudo/rakudo,usev6/rakudo,MasterDuke17/rakudo,softmoth/rakudo,b2gills/rakudo,jonathanstowe/rakudo,nbrown/rakudo,zostay/rakudo,salortiz/rakudo,samcv/rakudo,awwaiid/rakudo,raydiak/rakudo,rakudo/rakudo,salortiz/rakudo,tony-o/rakudo,MasterDuke17/rakudo,jonathanstowe/rakudo,nbrown/rakudo,Gnouc/rakudo,rakudo/rakudo,zostay/rakudo,labster/rakudo,nbrown/rakudo