RFR: 8310994: Add JFR event for selection operations [v5]

[Tim Prinzing]

> Added mirror event with static methods: jdk.internal.event.SelectionEvent that provides the duration of select calls and the count of how many keys are available.
> 
> Emit the event from SelectorImpl::lockAndDoSelect
> 
> Test at jdk.jfr.event.io.TestSelectionEvents

Tim Prinzing has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 16 commits:

 - update copyright dates
 - Merge branch 'master' into JDK-8310994
   
   # Conflicts:
   #	src/jdk.jfr/share/classes/jdk/jfr/internal/MirrorEvents.java
   #	src/jdk.jfr/share/classes/jdk/jfr/internal/instrument/JDKEvents.java
 - comment fixup
 - add select timeout field to the event
 - Change event generation:
   
   - selectNow is filtered out
   - select that times out is always sent
   - select without timeout uses duration test
 - rename event to SelectorSelect, field to selectionKeyCount.
 - Merge branch 'master' into JDK-8310994
 - remove trailing whitespace
 - event logic outside of the lock, selector in try block
 - remove unused import
 - ... and 6 more: https://git.openjdk.org/jdk/compare/36246c97...2e11e84a

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Changes: https://git.openjdk.org/jdk/pull/16710/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16710&range=04
  Stats: 321 lines in 9 files changed: 317 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/16710.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16710/head:pull/16710

PR: https://git.openjdk.org/jdk/pull/16710