RFR: 8343736: Test java/awt/Focus/UnaccessibleChoice/AccessibleChoiceTest.java failed: Choice can't be controlled by keyboard

[Damon Nguyen]

Test intermittently fails with a few different Exceptions. Initial report shows `Choice can't be controlled by keyboard` when failing. An additional report of an intermittent failure shows `Button does not have focus`.

Added some stability fixes. Additional delays, removed extraneous window, and added an additional focus check.

Debugged using additional screenshots during different failure points. Looks like sometimes the focus is still on the button. So, the delay has been added afterwards. Test passes on 22.04 Ubuntu machine with 100 repeats in CI. Also passed testing on all OS's with 50 repeats in CI.

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Commit messages:
 - Initial commit

Changes: https://git.openjdk.org/jdk/pull/22333/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22333&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8343736
  Stats: 29 lines in 1 file changed: 9 ins; 6 del; 14 mod
  Patch: https://git.openjdk.org/jdk/pull/22333.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22333/head:pull/22333

PR: https://git.openjdk.org/jdk/pull/22333