Gracefully shutdown forked tests in case of Stale threads.
As for now test exits VM without performing connection shutdown:
            if (results.count(Outcome.STALE) > 0) {
                testLog.println("Have stale threads, forcing VM to exit");
                testLog.flush();
                testLog.close();
                break;
            }
So we don't invoke BinaryLinkClient::close() to say to the Main part that the test is over. This leads to a SocketClosedException and a message
"<binary link had failed, forked VM corrupted the stream?"