RFR: 8378171: JFR: Copy of a closed recording should not be available

[Erik Gahlin]

Could I get a review of a PR that prevents closed recordings from being returned by FlightRecorder::getRecordings()?

The fix touches a lot of files and may seem unnecessary, but it will simplify the implementation of [JDK-8373439](https://bugs.openjdk.org/browse/JDK-8373439) later.

Testing: jdk/jdk/jfr

Thanks
Erik

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Commit messages:
 - Fix whitespace
 - Initial

Changes: https://git.openjdk.org/jdk/pull/29791/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=29791&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8378171
  Stats: 40 lines in 5 files changed: 26 ins; 1 del; 13 mod
  Patch: https://git.openjdk.org/jdk/pull/29791.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29791/head:pull/29791

PR: https://git.openjdk.org/jdk/pull/29791