[teststabilization] RFR: 8227539: Replace wildcard address with loopback or local host in tests - part 20

[Daniel Fuchs]

Hi,

Please find a patch that fixes some of the network test
to stop the using the wildcard issue whenever possible.

8227539: Replace wildcard address with loopback or local host in
          tests - part 20
https://bugs.openjdk.java.net/browse/JDK-8227539

webrev:
http://cr.openjdk.java.net/~dfuchs/webrev_8227539/webrev.00/


test/jdk/java/net/MulticastSocket/NoLoopbackPackets.java is the outlier
here. It's been observed failing because it was receiving packets
it didn't expect. The test is modified to skip packets that were
not sent by the test. This is achieved by making the payload
pseudo-unique.

best regards,

-- daniel