Testsuite enhancements for validating affinity processing

In order to test the interaction between a client and multiple servers (clustered and non-clustered), the EJB client testsuite currently provides a simple framework for:

• starting and stopping one or more servers, each on a given host and port (via DummyServer.java and DummyAssociationImpl.java)
• deploying named modules on such servers
• simulating a cluster of servers with a defined membership

The EJB client 4.0 testsuite is in need of more testing in these areas:

• affinity initialization (for stateful session beans) and
• affinity processing during invocation (for both stateful and stateless session beans)

This PR adds in test framework elements to address those issues, listed here:

• specify whether a deployed bean is stateful or stateless
• allow both stateful and stateless beans to be deployed on the same server
• to cause deployed beans to return a Result<T> object which contains the result (of type T) of the invocation as well as the node the invocation was invoked upon

These additional changes will allow writing test cases to validate the following:

• affinity initialization
• affinity processing
• lazy session creation