Refactor `AbstractSimpleTransportTestCase` and `MockTransportService` to not use `Version.transportVersion` 
x-pack/plugin/security/src/test/java/org/elasticsearch/xpack/security/transport/netty4/SimpleSecurityNetty4ServerTransportTests.java
.put("transport.profiles.client.xpack.security.ssl.enabled", true)
            .put("transport.profiles.client.xpack.security.ssl.certificate", testnodeCert)
            .put("transport.profiles.client.xpack.security.ssl.key", testnodeKey)
            .put("transport.profiles.client.xpack.security.ssl.client_authentication", value)
            .build();
        try (MockTransportService service = buildService("TS_PROFILE_REQUIRE_CLIENT_AUTH", Version.CURRENT, settings)) {
            TcpTransport originalTransport = (TcpTransport) service.getOriginalTransport();
            TransportAddress clientAddress = originalTransport.profileBoundAddresses().get("client").publishAddress();
            DiscoveryNode node = new DiscoveryNode(service.getLocalNode().getId(), clientAddress, service.getLocalNode().getVersion());
            try (Transport.Connection connection2 = openConnection(serviceA, node, TestProfiles.LIGHT_PROFILE)) {
                sslEngine = getEngineFromAcceptedChannel(originalTransport, connection2);
                assertEquals("client", getAcceptedChannel(originalTransport, connection2).getProfile());
                assertThat(sslEngine.getNeedClientAuth(), is(true));
                assertThat(sslEngine.getWantClientAuth(), is(false));
            }
        }
        
        value = randomCapitalization(SslClientAuthenticationMode.NONE);
        settings = Settings.builder()
            .put("transport.profiles.client.port", "8000-9000")
            .put("transport.profiles.client.xpack.security.ssl.enabled", true)
            .put("transport.profiles.client.xpack.security.ssl.certificate", testnodeCert)
            .put("transport.profiles.client.xpack.security.ssl.key", testnodeKey)
            .put("transport.profiles.client.xpack.security.ssl.client_authentication", value)
            .build();
        try (MockTransportService service = buildService("TS_PROFILE_NO_CLIENT_AUTH", Version.CURRENT, settings)) {
            TcpTransport originalTransport = (TcpTransport) service.getOriginalTransport();
            TransportAddress clientAddress = originalTransport.profileBoundAddresses().get("client").publishAddress();
            DiscoveryNode node = new DiscoveryNode(service.getLocalNode().getId(), clientAddress, service.getLocalNode().getVersion());
            try (Transport.Connection connection2 = openConnection(serviceA, node, TestProfiles.LIGHT_PROFILE)) {