RFR: 8316387: Exclude more failing multicast tests on AIX after JDK-8315651

[Christoph Langer]

[JDK-8315651](https://bugs.openjdk.org/browse/JDK-8315651) has removed a facility to hide errors of the type that is described in [JDK-8308807](https://bugs.openjdk.org/browse/JDK-8308807) from the test scaffolding.

Now we see more multicast tests failing on AIX and we should exclude them with reference to [JDK-8308807](https://bugs.openjdk.org/browse/JDK-8308807).

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Commit messages:
 - JDK-8316387

Changes: https://git.openjdk.org/jdk/pull/15770/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15770&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8316387
  Stats: 16 lines in 1 file changed: 10 ins; 5 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/15770.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15770/head:pull/15770

PR: https://git.openjdk.org/jdk/pull/15770