RFR: 7769: Cleanup pom and project files for JMC core

Wed Apr 13 23:42:33 UTC 2022

There is a lot of redundancy, whitespace errors, inconsistencies, obsolete stuff, errors, outdated plugin versions etc. in JMC core pom and project files.

org.openjdk.jmc.flightrecorder.writer.test and org.openjdk.jmc.jdp.test have been refactored in terms of layout like the other test projects.

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Commit messages:
 - Cleanup pom and project files for JMC core

Changes: https://git.openjdk.java.net/jmc/pull/398/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jmc&pr=398&range=00
  Issue: https://bugs.openjdk.java.net/browse/JMC-7769
  Stats: 697 lines in 73 files changed: 142 ins; 191 del; 364 mod
  Patch: https://git.openjdk.java.net/jmc/pull/398.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/398/head:pull/398

PR: https://git.openjdk.java.net/jmc/pull/398