RFR: 8308593: Add Keepalive Extended Socket Options Support for Windows [v4]

[Terry Chow]

> The PR adds support for the keepalive extended socket options on Windows. For TCP_KEEPIDLE and TCP_KEEPINTVL, these options are supported starting from Windows 10 version 1709. TCP_KEEPCNT is supported starting from Windows 10 version 1703. Information on these socket options can be found [here](https://learn.microsoft.com/en-us/windows/win32/winsock/ipproto-tcp-socket-options).
> 
> I've also corrected the `handleError()` function. On Windows, the error needs to be retrieved using `WSAGetLastError()` and error codes are prefixed with "WSA". Information on this can be found [here](https://learn.microsoft.com/en-us/windows/win32/winsock/error-codes-errno-h-errno-and-wsagetlasterror-2).
> 
>>The error codes returned by Windows Sockets are similar to UNIX socket error code constants, but the constants are all prefixed with WSA.
> 
>>Error codes set by Windows Sockets are not made available through the errno variable.
> 
> No new tests were added as the existing tests should cover this.

Terry Chow has updated the pull request incrementally with one additional commit since the last revision:

  Fixed inconsistent 'keep' vs. 'Keep' in method names

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Changes:
  - all: https://git.openjdk.org/jdk/pull/14232/files
  - new: https://git.openjdk.org/jdk/pull/14232/files/45173629..6944596c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14232&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14232&range=02-03

  Stats: 48 lines in 9 files changed: 0 ins; 0 del; 48 mod
  Patch: https://git.openjdk.org/jdk/pull/14232.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14232/head:pull/14232

PR: https://git.openjdk.org/jdk/pull/14232