RFR: 8376290: SocketChannel.finishConnect() contains confusing "getsockopt" in exception message for a failed connect() on Windows [v5]

[Jaikiran Pai]

> Can I please get a review of this change which proposes to remove the confusing "getsockopt" text from the exception reported on Windows when `SocketChannel.finishConnect()` raises an exception due to a failed `connect()`? 
> 
> This addresses https://bugs.openjdk.org/browse/JDK-8376290 and as noted in that issue, this looks like an oversight when changes were done for https://bugs.openjdk.org/browse/JDK-8317603. Prior to that, on older versions the exception reported on Windows was:
> 
> 
> java.net.ConnectException: Connection refused: no further information
> 
> 
> With the current proposed changes in this PR, the exception will now be `java.net.ConnectException: Connection refused` which matches what we report on *nix platforms.
> 
> A new jtreg test has been added to reproduce the original text and verify the change. tier1, tier2 and tier3 continue to pass with this change.

Jaikiran Pai has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 10 additional commits since the last revision:

 - merge latest from master branch
 - fix assumption in test
 - merge latest from master branch
 - replace TestAbortedException with Assumptions.assumeTrue
 - skip the test if the SocketChannel unexpectedly connects to the destination address
 - rename test to ConnectionRefusedMessage
 - formatting
 - add bug id to the test
 - allow NULL for msg in NET_ThrowNew
 - introduce test

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/29409/files
  - new: https://git.openjdk.org/jdk/pull/29409/files/c184f07a..b57b088e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29409&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29409&range=03-04

  Stats: 3279 lines in 133 files changed: 1600 ins; 833 del; 846 mod
  Patch: https://git.openjdk.org/jdk/pull/29409.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29409/head:pull/29409

PR: https://git.openjdk.org/jdk/pull/29409