RFR: 8308807: [AIX] MulticastSocket and jdp test fails due to joinGroup

[Deepa Kumari]

DatagramSocket delegates to an inner DatagramSocket object. Irrespective of whether datagramSocket is IPv4 or IPv6, we create an IPv6 datagramChannel as its's delegate. So, This can cause problems with operations like joinGroup. 

On AIX, IPv6 datagramSocket can not join an IPv4 multicast group.

These failures can be fixed by making sure that the delegate created for a datagram socket has the same protocol family. 




Reported Issue : [JDK-8308807](https://bugs.openjdk.org/browse/JDK-8308807)

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Commit messages:
 - 8308807: [AIX] MulticastSocket and jdp test fails due to joinGroup

Changes: https://git.openjdk.org/jdk/pull/14142/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14142&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8308807
  Stats: 12 lines in 2 files changed: 11 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/14142.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14142/head:pull/14142

PR: https://git.openjdk.org/jdk/pull/14142