RFR: 8359598: [TestBug] VirtualFlowTestUtils should not create a temporary Stage [v2]

[Marius Hanl]

On Thu, 10 Jul 2025 19:43:15 GMT, Andy Goryachev <angorya at openjdk.org> wrote:

>> I thought about this as well. No strong opinion from my side.
>
> there should be no noise: it's more of a question of instructing the developer why their test failed.  if there is no message, the NPE will happen in the context of the failing test which makes it rather obvious.  I agree with @Maran23 , either way is fine.

Since they were two similar opinions about this, I added an exception with a clear message why the flow might be null. :)

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PR Review Comment: https://git.openjdk.org/jfx/pull/1829#discussion_r2202499498