RFR: 8280241: (aio) java/foreign/channels/TestAsyncSocketChannels fails in IPv6 only env with ExceptionInInitializerError

[Daniel Jeliński]

When IPv4 is disabled on a Windows system, `socket(AF_INET,...)` calls fail with `WSAEAFNOSUPPORT`.
The socket is only needed to retrieve the address of ConnectEx method, and an IPv6 socket serves that purpose equally well.

The patch was verified on a Windows 10 machine with IPv4 disabled using `netsh interface ipv4 uninstall`. Some tests are still failing, but `TestAsyncSocketChannels` is passing now.

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Commit messages:
 - Fix ConnectEx address retrieval on IPv4-only Windows machines

Changes: https://git.openjdk.java.net/jdk/pull/7197/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7197&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8280241
  Stats: 8 lines in 2 files changed: 8 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7197.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7197/head:pull/7197

PR: https://git.openjdk.java.net/jdk/pull/7197