Fix rotate on empty list
Fix rotate on empty list

`my @a = (); @a.rotate(1)` used to error with `Modulation by zero`
before, but now does nothing.

Passes `make m-spectest`.

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