JBIDE-16254 common.model.test plugin stuck in Display.sleep() on hudson

Refactored delay to use Display.sleep() and Display.wake() to avoid
scenarios where display sleeps forever
JBIDE-8445 Do not create markers at internal attribute validation by XModel

Errors are saved into internal objects and are available
only for JBoss Tools XML editor.
Add prinln to track how wake up for display is processd on hudson