Only optimize literal Int in slices
Only optimize literal Int in slices

Fixes R#2185.  Proper handling of Ranges and Lists could be done here
but are out of the scope of fixing the problem at the moment.

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