RFR: 8360160: ubuntu-22-04 machine is failing client tests

[Damon Nguyen]

Ubuntu machine has multiple failing java awt tests. When looking at the screenshots of the desktop when each test fails, a white square can be seen at the top-left of the desktop.

<img width="803" height="344" alt="Screenshot 2025-08-20 at 10 06 37 AM" src="https://github.com/user-attachments/assets/52d023f6-18ff-46d4-98c4-e2e332ab6a03" />

This seems to be similar to the white square that `FrameVisualTest.java` creates so the frame was not disposed of properly during this failure. I have tried re-creating this failure on Ubuntu 22.04, similar to the failure OS that this originally occurred on, to no avail. I ran this test individually, and with all of the listed failing tests back-to-back but all the tests pass as normal. This stabilization fix to the test attempts to prevent this in case it occurs again.

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Commit messages:
 - Initial commit
 - Merge branch 'master' of github.com:DamonGuy/jdk
 - Merge branch 'master' of github.com:DamonGuy/jdk
 - Merge branch 'master' of github.com:DamonGuy/jdk
 - Merge branch 'master' of github.com:DamonGuy/jdk
 - Merge branch 'master' of github.com:DamonGuy/jdk
 - Merge branch 'master' of github.com:DamonGuy/jdk
 - Merge branch 'master' of github.com:DamonGuy/jdk
 - Merge branch 'master' of github.com:DamonGuy/jdk
 - Merge branch 'master' of github.com:DamonGuy/jdk
 - ... and 2 more: https://git.openjdk.org/jdk/compare/b69a3849...7f4a298f

Changes: https://git.openjdk.org/jdk/pull/26871/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26871&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8360160
  Stats: 17 lines in 1 file changed: 7 ins; 3 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/26871.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26871/head:pull/26871

PR: https://git.openjdk.org/jdk/pull/26871