ISPN-4474 ISPN-4473 Get remote events working in compatibility mode

https://issues.jboss.org/browse/ISPN-4474
https://issues.jboss.org/browse/ISPN-4473

* Fixes both ClassCastExceptions reported in these jiras.
* Adds remote event compatibility tests.
* Refactored remote event assertion code to be sharable between the Hot Rod client tests and the compatibility tests.
It's just a test class, so no :)