[JMX] Support registering an MXBean that extends MBeanRegistration

A DESCRIPTION OF THE PROBLEM :
Currently, an MXBean interface cannot extend the MBeanRegistration interface. It would be great to be able to support default method implementations on the MXBean interface, and not have to repeat those at the implementation class level.

For example, preRegister method could be implemented using a default method implementation on the MXBean interface.