Bug 75711 AstProvider should not create AST if requested by SelectionListenerWithASTManager
3.1 M2 If SelectionListenerWithASTManager waits for an AST and the editor closes we should not create an AST for that one but return null instead.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/JavaEditor.java
/**
		 * {@inheritDoc}
		 */
		public void setValue(String name, String value) {
			throw new UnsupportedOperationException();
		}
		/**
		 * {@inheritDoc}
		 */
		public void setValue(String name, boolean value) {
			throw new UnsupportedOperationException();
		}
		/**
		 * Returns the adapted options Map.
		 * 
		 * @return Returns the adapted options Map.
		 */
		public Map getOptions() {
			return fOptions;
		}
		/**
		 * Returns the mock-up preference store, events are received through this preference store.
		 * @return Returns the mock-up preference store.
		 */
		public IPreferenceStore getMockupPreferenceStore() {
			return fMockupPreferenceStore;
		}
		/**
		 * Set the event filter to the given filter.
		 *