RFR: 8319555: [TestBug] Utility for creating instruction window for manual tests

[Andy Goryachev]

Provides the base class for manual tests which displays the test instructions, the UI under test, and the Pass/Fail buttons.

Uses `EmojiTest` to illustrate the use of the new class.

Example:


public class ManualTestExample extends ManualTestWindow {
    public ManualTestExample() {
        super(
            "Manual Test Example",
            """
            Instructions:
            1. you will see a button named "Test"
            2. press the button
            3. verify that the button can be pressed""",
            400, 250
        );
     }

     public static void main(String[] args) throws Exception {
         launch(args);
     }

     @Override
     protected Node createContent() {
         return new Button("Test");
     }
}


![Screenshot 2025-03-28 at 11 50 16](https://github.com/user-attachments/assets/b44a7eb1-d98f-44a5-b13e-612b31c94c60)

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

Commit messages:
 - cleanup
 - 2025
 - Merge remote-tracking branch 'origin/master' into 8319555.manual
 - Merge branch 'master' into 8319555.manual
 - Merge branch 'master' into 8319555.manual
 - Merge remote-tracking branch 'origin/master' into 8319555.manual
 - Merge remote-tracking branch 'origin/8319555.manual' into 8319555.manual
 - removed example
 - cleanup
 - whitespace
 - ... and 9 more: https://git.openjdk.org/jfx/compare/ff777c7a...8f23a763

Changes: https://git.openjdk.org/jfx/pull/1747/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1747&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8319555
  Stats: 351 lines in 8 files changed: 290 ins; 47 del; 14 mod
  Patch: https://git.openjdk.org/jfx/pull/1747.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1747/head:pull/1747

PR: https://git.openjdk.org/jfx/pull/1747