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

Okay this approach seems reasonable and doesn't add a huge burden to running the tests.

Do we want to add this to all TEST.ROOT files or will hotspot and jdk suffice here?

The PR description should be updated and we probably need to expand this to other groups for review.

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

Marked as reviewed by dholmes (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/23054#pullrequestreview-2557838579