RFR: 8296923: JFR: jfr --version should return System.getProperty("java version")

[Erik Gahlin]

Could I have a review of a PR that changes the version of the jfr tool to that of the JDK.  

Testing: test/jdk/jdk/jfr/

Thanks
Erik

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Commit messages:
 - Initial

Changes: https://git.openjdk.org/jdk/pull/11132/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11132&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8296923
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/11132.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11132/head:pull/11132

PR: https://git.openjdk.org/jdk/pull/11132