Reinstate `is default` and exact arity tie-breaks
Reinstate `is default` and exact arity tie-breaks

MasterDuke17/rakudo,labster/rakudo,MasterDuke17/rakudo,rakudo/rakudo,salortiz/rakudo,MasterDuke17/rakudo,MasterDuke17/rakudo,salortiz/rakudo,labster/rakudo,MasterDuke17/rakudo,tbrowder/rakudo,rakudo/rakudo,labster/rakudo,rakudo/rakudo,tbrowder/rakudo,salortiz/rakudo,tbrowder/rakudo,labster/rakudo,labster/rakudo,rakudo/rakudo,salortiz/rakudo,tbrowder/rakudo,tbrowder/rakudo,labster/rakudo,salortiz/rakudo,rakudo/rakudo,salortiz/rakudo,MasterDuke17/rakudo,tbrowder/rakudo,rakudo/rakudo