RFR: JDK-8313804: JDWP support for -Djava.net.preferIPv6Addresses=system [v7]

[Chris Plummer]

On Thu, 21 Sep 2023 00:49:45 GMT, Liam Miller-Cushon <cushon at openjdk.org> wrote:

>> Please consider this fix for [JDK-8313804](https://bugs.openjdk.org/browse/JDK-8313804), which adds support to JDWP for `-Djava.net.preferIPv6Addresses=system`. Previously it only handled `-Djava.net.preferIPv6Addresses=true` and `-Djava.net.preferIPv6Addresses=false`.
>
> Liam Miller-Cushon has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Add more test cases

I think overall the changes look good. Before approving I'd like to run it on our internal test system, which has a very large number of hosts and platform types, but I'll wait to make sure there are no other changes before doing that.

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PR Review: https://git.openjdk.org/jdk/pull/15796#pullrequestreview-1636733286