[RM-6685] Enabling swig downcasting for COperatorResult getters

Created on 2021-09-15 15:15:34 by Ali Allaoui. % Done: 0

go deeper in python introspection, by enabling swig downcasting (casting a derived type from base class pointer) see: https://stackoverflow.com/questions/27392602/swig-downcasting-from-base-to-derived