RFR: 8338428: Print final VM flags for task [v4]

[David Holmes]

On Thu, 16 Jan 2025 06:12:01 GMT, Leonid Mesnik <lmesnik at openjdk.org> wrote:

>> Some VM flags might depend on the environment and it makes sense to log final flags so it is possible to get their value when investigating failures.
>> 
>> I added them to VMProps, so it is always dump final flags before running tests using "-XX:+PrintFlagsFinal".
>> 
>> Update:
>> There were intermittent compilation failures when I tried to use classes from testlibrary, so I rewrtite the code without them.
>
> Leonid Mesnik has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Added diagnostic flag

Can flags supplied by a test, or the user, interfere with that invocation?

Do you really want the xml format for this file?

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PR Review: https://git.openjdk.org/jdk/pull/23054#pullrequestreview-2554893748