6961062: (dc) Several DatagramChannel tests timeout or fail with "address already in use"

[Alan Bateman]

Chris - I need a reviewer to change some of the older DatagramChannel 
tests so they are don't use a fixed port (8888). They tests will hang 
indefinitely or fail with "address already in use" when port 8888 is 
used by something else. The webrev with the changes is here:
    http://cr.openjdk.java.net/~alanb/6961062/webrev/

Thanks,
Alan.