amendments to open/test/jdk/java/net/ipv6tests/Tests.java

 add a diagnostics to print the ports of the two endpoints involved in the datagramEcho test scenario


   public static void datagramEcho (DatagramSocket s1, DatagramSocket s2,
                                     InetAddress ia2)
        throws Exception {

        byte[] ba = "Hello world".getBytes();
        DatagramPacket p1;

        SocketAddress dest2 = null;
        if (ia2 != null) {
            dest2 = new InetSocketAddress (ia2, s2.getLocalPort());
            p1 = new DatagramPacket (ba, ba.length, dest2);
        } else {
            p1 = new DatagramPacket (ba, ba.length);
        }

        dprintln ("dest2 == " + dest2);
        dprintln ("sender  endpoint == " + s1.getLocalSocketAddress());
        dprintln ("echo endpoint == " + s2.getLocalSocketAddress());

        DatagramPacket r1 = new DatagramPacket (new byte[256], 256);
        DatagramPacket r2 = new DatagramPacket (new byte[256], 256);

        s1.send (p1);
        s2.receive (r1);
        s2.send (r1);
        s1.receive (r2);
        comparePackets (p1, r1);
        comparePackets (p1, r2);
    }