RFR: 8310996: Add JFR event for connect operations [v7]

[Tim Prinzing]

> Adds a JFR event for socket connect operations.
> 
> Existing tests TestSocketEvents and TestSocketChannelEvents modified to also check for connect events.

Tim Prinzing has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 11 commits:

 - Merge branch 'master' into JDK-8310996
   
   # Conflicts:
   #	src/java.base/share/classes/sun/nio/ch/NioSocketImpl.java
 - split socket connect failure out to its own event.
 - Added more tests for socket connect events.
   
   - SocketAdapter connect
   - SocketAdapter connect with exception
   - Socket connect with exception
   - SocketChannel connect with exception
   - SocketChannel non-blocking connect
   - SocketChannel non-blocking connect with exception
 - suggested changes
 - improved exception names and handling
 - Added support for connection failure and non-blocking connections.
   
   If an exception is thrown while attempting a connection, the message
   from the exception is stored in the event.  The start time of the
   initial connect call is stored and used when a finishConnect call is
   successful or an exception is thrown.
 - fix default settings
 - fix merge
 - Merge branch 'master' into JDK-8310996
   
   # Conflicts:
   #	src/jdk.jfr/share/classes/jdk/jfr/internal/JDKEvents.java
   #	src/jdk.jfr/share/classes/jdk/jfr/internal/MirrorEvents.java
 - added tests and support for sockets.
 - ... and 1 more: https://git.openjdk.org/jdk/compare/dfa5620f...a379609e

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Changes: https://git.openjdk.org/jdk/pull/21528/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21528&range=06
  Stats: 738 lines in 16 files changed: 686 ins; 7 del; 45 mod
  Patch: https://git.openjdk.org/jdk/pull/21528.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21528/head:pull/21528

PR: https://git.openjdk.org/jdk/pull/21528