RFR: 8266936: Add a finalization JFR event

[Markus Grönlund]

Greetings,

Object.finalize() was deprecated in JDK9. There is an ongoing effort to replace and mitigate Object.finalize() uses in the JDK libraries; please see https://bugs.openjdk.java.net/browse/JDK-8253568 for more information. 

We would also like to assist users in replacing and mitigating uses in non-JDK code.

Hence, this changeset adds a periodic JFR event to help identify which classes are overriding Object.finalize().

Thanks
Markus

-------------

Commit messages:
 - whitespace
 - update
 - update
 - whitespace
 - 8266936-alt: Add a finalization JFR event
 - shortcut calling Jfr::is_recording()
 - 8266936: Add a finalization JFR event

Changes: https://git.openjdk.java.net/jdk/pull/4731/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4731&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8266936
  Stats: 249 lines in 9 files changed: 248 ins; 1 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4731.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4731/head:pull/4731

PR: https://git.openjdk.java.net/jdk/pull/4731