Make sure X handles empty lists on RHS
Make sure X handles empty lists on RHS

Fixes R#2286

tbrowder/rakudo,MasterDuke17/rakudo,Gnouc/rakudo,tbrowder/rakudo,tony-o/rakudo,labster/rakudo,rakudo/rakudo,salortiz/rakudo,nbrown/rakudo,nbrown/rakudo,MasterDuke17/rakudo,MasterDuke17/rakudo,Gnouc/rakudo,labster/rakudo,salortiz/rakudo,salortiz/rakudo,Gnouc/rakudo,rakudo/rakudo,softmoth/rakudo,labster/rakudo,nbrown/rakudo,Gnouc/rakudo,tbrowder/rakudo,Gnouc/rakudo,MasterDuke17/rakudo,salortiz/rakudo,rakudo/rakudo,rakudo/rakudo,salortiz/rakudo,rakudo/rakudo,labster/rakudo,softmoth/rakudo,labster/rakudo,softmoth/rakudo,MasterDuke17/rakudo,softmoth/rakudo,nbrown/rakudo,tony-o/rakudo,nbrown/rakudo,tbrowder/rakudo,tony-o/rakudo,tony-o/rakudo,labster/rakudo,MasterDuke17/rakudo,tony-o/rakudo,rakudo/rakudo,tbrowder/rakudo,nbrown/rakudo,tony-o/rakudo,Gnouc/rakudo,salortiz/rakudo,tbrowder/rakudo,softmoth/rakudo