Fix Supply.head(*-3)
Fix Supply.head(*-3)

- makes it consistent with List.head(*-3)
- fixes R#3746

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