RFR: 8328716: [TestBug] Screen capturing utility for failed tests [v2]

[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.
> 
> A possible improvement could be to output a data URL
> 
> `data:image/png;base64,iVBORw0KGgoAAAANSUhEU...`
> 
> so it can be rendered in Safari (Chrome truncates the image possibly due to following a url length limit)

Andy Goryachev has updated the pull request incrementally with two additional commits since the last revision:

 - testing: inject a failure
 - review comments

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

Changes:
  - all: https://git.openjdk.org/jfx/pull/1746/files
  - new: https://git.openjdk.org/jfx/pull/1746/files/042b5838..c7bdcee7

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1746&range=01
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1746&range=00-01

  Stats: 143 lines in 4 files changed: 6 ins; 134 del; 3 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