RFR: 8294156: Allow PassFailJFrame.Builder to create test UI

[Alexander Zvegintsev]

On Tue, 12 Sep 2023 13:37:09 GMT, Alexey Ivanov <aivanov at openjdk.org> wrote:

> However, to test this case I'll need a (simple) scenario where multiple windows are created.

For example `test/jdk/java/awt/event/MouseEvent/SpuriousExitEnter/SpuriousExitEnter_2.java` is not converted to use PassFailJFrame, but shows instruction window and two test windows.

For these test windows, we can safely reduce the width a lot and arrange them in a row.
![image](https://github.com/openjdk/jdk/assets/77687766/9c7f3548-fa0a-4e1f-ad87-a7af7561064b)

Probably we could add some other sophisticated layouts later, e.g.:
![image](https://github.com/openjdk/jdk/assets/77687766/a9da5948-9f52-420e-8f15-55818fe8f255)

But this kind of layout seems to be beyond the scope of this PR, I just wish we hadn't missed the option to add multiple windows at once.

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PR Review Comment: https://git.openjdk.org/jdk/pull/15665#discussion_r1323425586