RFR: 8328716: [TestBug] Screen capturing utility for failed tests [v8]

[Andy Goryachev]

> Introduce a facility, in the form of JUnit5 annotation, to allow for capturing a desktop screenshot of a failed test.
> 
> The primary intent is to be able to debug an intermittent test case, rather than wholesale addition of the new annotation to all the tests.
> 
> The log contains a base-64 encoded screenshot (like this: `data:image/png;base64,iVBORw0KGgoAAAANSUhEU...` )
> so it can be rendered in Safari (Chrome truncates the image possibly due to following a url length limit)
> 
> Additionally, provided a utility class to capture the screenshots at the specific point in a test and write it to stdout/stderr:
> 
> 
> // write a base-64 encoded screenshot to stderr
> ScreenshotCapture.writeScreenshot(System.err);
> 
> 
> Example:
> 
> ![jenkins-screenshot](https://github.com/user-attachments/assets/abebd76f-747a-4d6d-a9a6-63c6e9426830)

Andy Goryachev has updated the pull request incrementally with one additional commit since the last revision:

  stderr

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

Changes:
  - all: https://git.openjdk.org/jfx/pull/1746/files
  - new: https://git.openjdk.org/jfx/pull/1746/files/8668ebb1..96187a01

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1746&range=07
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1746&range=06-07

  Stats: 8 lines in 2 files changed: 0 ins; 2 del; 6 mod
  Patch: https://git.openjdk.org/jfx/pull/1746.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1746/head:pull/1746

PR: https://git.openjdk.org/jfx/pull/1746