RFR: 8351187: Add JFR monitor notification event [v4]

[Aleksey Shipilev]

> We have `JavaMonitorWait` event, but no symmetric `JavaMonitorNotify` event. Notifications are important/interesting to track as well, for example to correlate the delay between notification and eventual wake up.
> 
> Providing this event would also replace one of of the RT counters that are going away in [JDK-8348829](https://bugs.openjdk.org/browse/JDK-8348829).
> 
> This counter is disabled by default to keep any potential impact low. We can consider flipping it to enabled by default later.
> 
> Additional testing:
>  - [x] Linux x86_64 server fastdebug, `jdk_jfr`

Aleksey Shipilev has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains seven commits:

 - Only emit event when notification happened
 - Merge branch 'master' into JDK-8351187-jfr-monitor-notify
 - Rewrite test to RecordingStream
 - Drop threshold to 0ms
 - Merge branch 'master' into JDK-8351187-jfr-monitor-notify
 - Disable by default
 - Fix

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Changes: https://git.openjdk.org/jdk/pull/23901/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23901&range=03
  Stats: 168 lines in 7 files changed: 162 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/23901.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23901/head:pull/23901

PR: https://git.openjdk.org/jdk/pull/23901