Deadlocks using TestMsbAdapterFactory

[sebastiaansamyn-tc]

We have run into a deadlock while running tests with the TestMsbAdapterFactory as brokerAdapterFactory. In our case it happened when we had a responder server that handed off the work to another thread that then tried to send a response with the responder that it got from the response context.

The problem seems to be that multiple threads access methods on the TestMsbStorageForAdapterFactory instance of that factory concurrently and everything is synchronized, so the entire thing deadlocks.

It looks like this could be solved by using java.util.concurrent.ConcurrentMap instances.