syncNativeQueue() throws an OperationTimedOut: 20001 exception.

Exception in thread "AWT-EventQueue-0" sun.awt.SunToolkit$OperationTimedOut: 20001
at sun.awt.X11.XToolkit.syncNativeQueue(XToolkit.java:2411)
at sun.awt.SunToolkit$3.dispatch(SunToolkit.java:1646)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:752)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:705)
at java.awt.EventQueue$3.run(EventQueue.java:699)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:722)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:190)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:115)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:104)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:100)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:92)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:81)

The issue may be similar to JDK-8049032 and others, but the stacktracke does not contains actual realSync() call.

To reproduce the problem run the attached RealsyncTimeout.java test. To compile it use additionally ExtendedRobot class from here:
http://hg.openjdk.java.net/jdk9/jdk9/jdk/raw-file/tip/test/lib/testlibrary/ExtendedRobot.java

The tests can fail occasionally. And may not. The failure is not stable.