RFR: 8365815: JFR: Update metadata.xml with 'jfr query' examples [v3]

[Erik Gahlin]

> Could I have a review of a PR that adds a couple of 'jfr query' examples to metadata.xml?
> 
> It turns out that the EventDuration event doesn't work because it has no fields. The fix is to remove the class-specific commit() method and constructor for events without fields.
> 
> Testing: test/jdk/jdk/jfr + tier1
> 
> Thanks
> Erik

Erik Gahlin has updated the pull request incrementally with one additional commit since the last revision:

  Add s

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/26869/files
  - new: https://git.openjdk.org/jdk/pull/26869/files/9d54c0e5..d6c88bb0

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26869&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26869&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/26869.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26869/head:pull/26869

PR: https://git.openjdk.org/jdk/pull/26869