RFR: 8310996: Add JFR event for connect operations [v6]

[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 incrementally with one additional commit since the last revision:

  split socket connect failure out to its own event.

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/21528/files
  - new: https://git.openjdk.org/jdk/pull/21528/files/13f81570..f7b3be00

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21528&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21528&range=04-05

  Stats: 327 lines in 16 files changed: 240 ins; 21 del; 66 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