Create concrete type object before calling body block
Create concrete type object before calling body block

The body block code can know it's concretization (incomplete though)
from `$*MOP-ROLE-CONCRETIZATION`. Though user code will have it in
preset in `$?CONCRETIZATION`.

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