Refactor `AbstractSimpleTransportTestCase` and `MockTransportService` to not use `Version.transportVersion` 
test/framework/src/main/java/org/elasticsearch/transport/AbstractSimpleTransportTestCase.java
};
            t.start();
            ConnectionProfile.Builder builder = new ConnectionProfile.Builder();
            builder.addConnections(
                1,
                TransportRequestOptions.Type.BULK,
                TransportRequestOptions.Type.PING,
                TransportRequestOptions.Type.RECOVERY,
                TransportRequestOptions.Type.REG,
                TransportRequestOptions.Type.STATE
            );
            builder.setHandshakeTimeout(TimeValue.timeValueHours(1));
            ConnectTransportException ex = expectThrows(
                ConnectTransportException.class,
                () -> connectToNode(serviceA, dummy, builder.build())
            );
            assertEquals("[][" + dummy.getAddress() + "] general node connection failure", ex.getMessage());
            assertThat(ex.getCause().getMessage(), startsWith("handshake failed"));
            t.join();
        }
    }
    public void testResponseHeadersArePreserved() throws InterruptedException {
        List<String> executors = new ArrayList<>(ThreadPool.THREAD_POOL_TYPES.keySet());
        CollectionUtil.timSort(executors); 
        serviceA.registerRequestHandler("internal:action", ThreadPool.Names.SAME, TestRequest::new, (request, channel, task) -> {
            threadPool.getThreadContext().putTransient("boom", new Object());
            threadPool.getThreadContext().addResponseHeader("foo.bar", "baz");
            if ("fail".equals(request.info)) {
                throw new RuntimeException("boom");
            } else {