RFR: 8345447: test/jdk/javax/swing/JToolBar/4529206/bug4529206.java fails in ubuntu22.04

[Prasanta Sadhukhan]

test/jdk/javax/swing/JToolBar/4529206/bug4529206.java fails in OCI system citing

Caused by: java.lang.RuntimeException: setFloating does not work correctly
at bug4529206.lambda$main$3(bug4529206.java:90)
at java.desktop/java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:308) 

which suggests that the focus is not shifted from main frame to toolbar..
Added a stability waitForIdle and test passed in several OCI systems

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Commit messages:
 - test fix

Changes: https://git.openjdk.org/jdk/pull/22536/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22536&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8345447
  Stats: 4 lines in 1 file changed: 1 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/22536.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22536/head:pull/22536

PR: https://git.openjdk.org/jdk/pull/22536