Provide two cluster test case for EJBClient

The Wildfly test suite is missing a test case for testing EJBClient interactions over two clusters, which does exist in the EAP test cycle. This test case aims to duplicate that multi-node SmartFrog test in the Wildfly testsuite so that errors are identified early.

The test setup:

• two clusters

   ejb-forwarder = {node0, node1}
   ejb={node3, node4}
  

  where each node of cluster ejb-forwarder has a remote outbound connection to node3

• a forwarding SFSB deployment on cluster ejb-forwarder, which forwards invocations to cluster ejb
• a non-forwarding deployment on cluster ejb
• a client which makes invocations on the clustered deployment on ejb-forwarder every 10 ms

The test execution:

• once the servers and deployments have been deployed, each server is shut down and then restarted in turn, at which time the test ends.

The expected behaviour:

• at least 90% of client invocations will complete without exception
• test client invocations on ejb-forwarder will fail over from node0 to node1 (or vice versa, depending on which node of cluster ejb-forwarder is down)
• server-client invocations on ejb will fail-over from node3 to node 4 (or vice versa depending on which node of cluster ejb is down)

The invocation transaction attribute set up:

• invocations from the client to ejb-forwarder are not in transaction scope
• invocations from ejb-forwarder to ejb are in transaction scope with attribute REQUIRED

This allows exercising invocations from a managed transaction context, which uncovered a number of issues...