Integrated: 8336332: Rework tests to avoid unrelated stderr output

[Andy Goryachev]

On Thu, 11 Sep 2025 22:09:10 GMT, Andy Goryachev <angorya at openjdk.org> wrote:

> This PR removes unrelated `stderr` output in the headless test logs by redirecting it to an in-memory buffer.  Exceptions found in the buffer can be checked against the expected list.
> 
> In the case when any mismatch is detected, whether the type or the number of exceptions of particular type, the accumulated buffer gets dumped to `stderr` and the test fails.
> 
> ## How To
> 
> To redirect stderr and later check the exceptions, surround your code with
> 
> `OutputRedirect.suppressStderr()` and either `OutputRedirect.checkStderr()` or `OutputRedirect.checkAndRestoreStderr()` (ideally, in the `finally` block).
> 
> To simply undo redirection, without checking, call  `OutputRedirect.restoreStderr()`.
> 
> To add the check to all the tests in the file, one can call the above mentioned methods inside  `@BeforeEach` and `@AfterEach`.
> 
> ## Changes
> 
> - added `OutputRedirect` facility
> 
> ## Miscellaneous
> 
> `ErrorLoggingUtiltity` name will be fixed in a followup https://bugs.openjdk.org/browse/JDK-8367995

This pull request has now been integrated.

Changeset: f4b3d552
Author:    Andy Goryachev <angorya at openjdk.org>
URL:       https://git.openjdk.org/jfx/commit/f4b3d55200d519c89f34f0c30f15e1da0323efc0
Stats:     494 lines in 18 files changed: 433 ins; 19 del; 42 mod

8336332: Rework tests to avoid unrelated stderr output

Reviewed-by: kcr, arapte

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PR: https://git.openjdk.org/jfx/pull/1897