RFR: 8373704: Improve "SocketException: Protocol family unavailable" message [v2]

[Matthias Baesken]

> In [JDK-8373676](https://bugs.openjdk.org/browse/JDK-8373676)
> we noticed a "SocketException: Protocol family unavailable" because of missing ipv6 support. We could improve this exception and tell that the ipv6 support is not available or something related.

Matthias Baesken has updated the pull request incrementally with one additional commit since the last revision:

  Adjust the message as suggested by jaikiran

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Changes:
  - all: https://git.openjdk.org/jdk/pull/28851/files
  - new: https://git.openjdk.org/jdk/pull/28851/files/ca4952cd..efaa1512

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28851&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28851&range=00-01

  Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/28851.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28851/head:pull/28851

PR: https://git.openjdk.org/jdk/pull/28851