RFR: 8303911: [testbug] Some unit tests call System.exit

[Lukasz Kostyra]

On Wed, 19 Apr 2023 18:15:40 GMT, Lukasz Kostyra <lkostyra at openjdk.org> wrote:

> Changes added to this commit resolve cases where `System.exit()` was used to leave tests abruptly. These tests, if System.exit() is hit, could potentially create some unwanted behavior from JTest (ex. silently skipping these tests instead of failing them).
> 
> There were some files which I did not modify, mostly because they were a part of a test sub-app, or tests would require major rework to make it work.
> 
> Two FXML tests were performance tests already written as separate apps, so I moved them to appropriate directory in tests/performance.

I also noticed I did not update some copyright boilerplates with current dates

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PR Comment: https://git.openjdk.org/jfx/pull/1101#issuecomment-1516144761