RFR: 8310996: Add JFR event for connect operations [v9]

[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:

  Refactored connect exception tests to a single IOHelper method
  that takes a function argument that is excpected to produce the
  appropriate exception.  IANA reserved ports in the range 225 to
  241 are used to attempt to produce a connect exception.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/21528/files
  - new: https://git.openjdk.org/jdk/pull/21528/files/5e55ffc6..81cea489

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21528&range=08
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21528&range=07-08

  Stats: 206 lines in 4 files changed: 54 ins; 114 del; 38 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