Make a lot of Cool multi methods handle Nil invocant better
Make a lot of Cool multi methods handle Nil invocant better

Also make sure that if a Failure is passed (which is a subclass of
Nil), that that is thrown when trying to warn or die.

tony-o/rakudo,tbrowder/rakudo,tony-o/rakudo,rakudo/rakudo,tony-o/rakudo,MasterDuke17/rakudo,MasterDuke17/rakudo,MasterDuke17/rakudo,rakudo/rakudo,MasterDuke17/rakudo,rakudo/rakudo,salortiz/rakudo,rakudo/rakudo,labster/rakudo,MasterDuke17/rakudo,labster/rakudo,tbrowder/rakudo,rakudo/rakudo,tony-o/rakudo,salortiz/rakudo,tbrowder/rakudo,labster/rakudo,tony-o/rakudo,labster/rakudo,labster/rakudo,labster/rakudo,tony-o/rakudo,MasterDuke17/rakudo,rakudo/rakudo,tbrowder/rakudo,salortiz/rakudo,salortiz/rakudo,salortiz/rakudo,tbrowder/rakudo,salortiz/rakudo,tbrowder/rakudo