RFR: 8337320: Update ProblemList.txt with tests known to fail on XWayland

[Alexander Zvegintsev]

Adding tests failing on XWayland.

The `java/awt/Focus/VetoableChangeListenerLoopTest.java` mentioned in the bug description no longer fails.

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Commit messages:
 - 8337320: Update ProblemList.txt with tests known to fail on XWayland

Changes: https://git.openjdk.org/jdk/pull/20384/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20384&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8337320
  Stats: 6 lines in 1 file changed: 6 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/20384.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20384/head:pull/20384

PR: https://git.openjdk.org/jdk/pull/20384