Refactor `AbstractSimpleTransportTestCase` and `MockTransportService` to not use `Version.transportVersion` 
test/framework/src/main/java/org/elasticsearch/transport/AbstractSimpleTransportTestCase.java
AtomicInteger requestsReceived = new AtomicInteger();
            AtomicInteger requestsSent = new AtomicInteger();
            AtomicInteger responseReceived = new AtomicInteger();
            AtomicInteger responseSent = new AtomicInteger();
            @Override
            public void onRequestReceived(long requestId, String action) {
                if (action.equals(ACTION)) {
                    requestsReceived.incrementAndGet();
                }
            }
            @Override
            public void onResponseSent(long requestId, String action, TransportResponse response) {
                if (action.equals(ACTION)) {
                    responseSent.incrementAndGet();
                }
            }
            @Override
            public void onResponseSent(long requestId, String action, Exception error) {
                if (action.equals(ACTION)) {
                    responseSent.incrementAndGet();
                }
            }
            @Override
            @SuppressWarnings("rawtypes")
            public void onResponseReceived(long requestId, Transport.ResponseContext context) {
                if (context.action().equals(ACTION)) {