RFR: 7514: Rule for FinalizationStatistics

Mon Jan 16 18:30:56 UTC 2023

A new `jdk.FinalizerStatistics` JFR event was introduced in JDK 18. This pull requests adds a simple rule that makes use of it:
![Screenshot 2022-11-30 at 14 19 49](https://user-images.githubusercontent.com/10694593/204806915-0da90fe3-ccc0-430e-96f8-ebc529f8e7a1.png)

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Commit messages:
 - Remove Datadog from copyright header of files that were simply modified
 - Add Datadog to copyright header in modified files
 - Add proper unit test for new rule
 - Fix JFR rule tests
 - 7514: Add rule for finalizers run

Changes: https://git.openjdk.org/jmc/pull/456/files
 Webrev: https://webrevs.openjdk.org/?repo=jmc&pr=456&range=00
  Issue: https://bugs.openjdk.org/browse/JMC-7514
  Stats: 543 lines in 11 files changed: 538 ins; 0 del; 5 mod
  Patch: https://git.openjdk.org/jmc/pull/456.diff
  Fetch: git fetch https://git.openjdk.org/jmc pull/456/head:pull/456

PR: https://git.openjdk.org/jmc/pull/456