Refactor `AbstractSimpleTransportTestCase` and `MockTransportService` to not use `Version.transportVersion` 
x-pack/plugin/security/src/test/java/org/elasticsearch/xpack/security/transport/netty4/SimpleSecurityNetty4ServerTransportTests.java
assertThat(acceptedChannel.getProfile(), equalTo("_remote_cluster"));
            }
            
            final Settings qcSettings3 = Settings.builder()
                .put("xpack.security.remote_cluster_client.ssl.certificate_authorities", testnodeCert)
                .put("xpack.security.remote_cluster_client.ssl.verification_mode", "full")
                .build();
            try (
                MockTransportService qcService = buildService("QC", Version.CURRENT, qcSettings3);
                Transport.Connection connection = openConnection(qcService, node, connectionProfile)
            ) {
                assertThat(connection, instanceOf(StubbableTransport.WrappedConnection.class));
                Transport.Connection conn = ((StubbableTransport.WrappedConnection) connection).getConnection();
                assertThat(conn, instanceOf(TcpTransport.NodeChannels.class));
                TcpTransport.NodeChannels nodeChannels = (TcpTransport.NodeChannels) conn;
                for (TcpChannel channel : nodeChannels.getChannels()) {
                    assertFalse(channel.isServerChannel());
                    assertThat(channel.getProfile(), equalTo("_remote_cluster"));
                    final SSLEngine sslEngine = SSLEngineUtils.getSSLEngine(channel);
                    assertThat(sslEngine.getUseClientMode(), is(true));
                }
                final TcpChannel acceptedChannel = getAcceptedChannel(originalTransport, connection);
                assertThat(acceptedChannel.getProfile(), equalTo("_remote_cluster"));
            }
        }
    }
    public void testRemoteClusterCanWorkWithoutSSL() throws Exception {
        final ConnectionProfile connectionProfile = ConnectionProfile.resolveConnectionProfile(
            new ConnectionProfile.Builder().setTransportProfile("_remote_cluster")
                .addConnections(