Optimize previous changes to method roles when transitive
Optimize previous changes to method roles when transitive

It's not necessary to apply c3_merge on each method invocation, just the
first one would suffice.

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