RFR: 8261: Use test flag to skip JDP multicast tests in JolokiaTest [v3]

[Martin Skarsaune]

> I just became aware that there is a new flag used to skip JDP tests. 
> I previously added some env checking to skip similar multicast tests for Jolokia. 
> Hence it would be a lot cleaner to use the new standardized mechanism for this.
> Trying out whether this fixes [JMC-8261](https://bugs.openjdk.org/browse/JMC-8261)

Martin Skarsaune has updated the pull request incrementally with one additional commit since the last revision:

  JMC-8261: Spotless fix

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Changes:
  - all: https://git.openjdk.org/jmc/pull/588/files
  - new: https://git.openjdk.org/jmc/pull/588/files/5b20ff65..89e34aaf

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jmc&pr=588&range=02
 - incr: https://webrevs.openjdk.org/?repo=jmc&pr=588&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jmc/pull/588.diff
  Fetch: git fetch https://git.openjdk.org/jmc.git pull/588/head:pull/588

PR: https://git.openjdk.org/jmc/pull/588