RFR: 8329138: Convert JFR FileForceEvent to static mirror event

[Tim Prinzing]

Currently the JFR event FileForceEvent is generated by instrumenting the sun.nio.ch.FileChannelImpl class. This needs to be changed to use the newer mirror events with static methods.

Added the event at jdk.internal.event.FileForceEvent, and changed jdk.jfr.events.FileForceEvent to be a mirror event.

Updated FileChannelImpl to use the jdk internal event static methods, and removed the force() method from FileChannelImplInstrumentor.

Uses the existing tests.

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Commit messages:
 - javadoc fixup
 - remove mirrors from JDKEvents
 - 8329138: Convert JFR FileForceEvent to static mirror event

Changes: https://git.openjdk.org/jdk/pull/18542/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18542&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8329138
  Stats: 159 lines in 7 files changed: 123 ins; 30 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/18542.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18542/head:pull/18542

PR: https://git.openjdk.org/jdk/pull/18542