RFR: 8277957: Add test group for IPv6 exclusive testing [v2]

[Ivan Šipka]

> Adding test group for IPv6 exclusive testing.

Ivan Šipka has updated the pull request incrementally with one additional commit since the last revision:

  added comment for adding the ipv6_only  testgroup

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/6600/files
  - new: https://git.openjdk.java.net/jdk/pull/6600/files/d89e3865..e3e24090

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=6600&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=6600&range=00-01

  Stats: 2 lines in 1 file changed: 2 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6600.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6600/head:pull/6600

PR: https://git.openjdk.java.net/jdk/pull/6600