Refactor `AbstractSimpleTransportTestCase` and `MockTransportService` to not use `Version.transportVersion` 
test/framework/src/main/java/org/elasticsearch/transport/AbstractSimpleTransportTestCase.java
private final TransportService service;
            TestRequestHandler(TransportService service) {
                this.service = service;
            }
            @Override
            public void messageReceived(TestRequest request, TransportChannel channel, Task task) throws Exception {
                if (randomBoolean()) {
                    Thread.sleep(randomIntBetween(10, 50));
                }
                if (fail.get()) {
                    throw new IOException("forced failure");
                }
                if (randomBoolean() && request.resendCount++ < 20) {
                    DiscoveryNode node = randomFrom(nodeA, nodeB, nodeC);
                    logger.debug("send secondary request from {} to {} - {}", toNodeMap.get(service), node, request.info);
                    service.sendRequest(
                        node,
                        "internal:action1",
                        new TestRequest("secondary " + request.info),
                        TransportRequestOptions.EMPTY,