Bug 182190 [StatusHandling] [Wizards] getControl assert on wizard page has no message
M6 If you forget to set the control on your wizard page our assert gives no feedback. We need an error message.
bundles/org.eclipse.jface/src/org/eclipse/jface/wizard/WizardDialog.java
createPageControls();
                
                updateSizeForWizard(wizard);
                pageContainer.layout(true);
            }
        } else {
            
             
            
            int size = nestedWizards.size();
            if (size >= 2 && nestedWizards.get(size - 2) == wizard) {
				nestedWizards.remove(size - 1);
			} else {
				
                nestedWizards.add(wizard);
			}
        }
    }
    /* (non-Javadoc)
     * Method declared on IWizardContainer.
     */
    public void showPage(IWizardPage page) {
        if (page == null || page == currentPage) {
            return;
        }
       
        if (!isMovingToPreviousPage) {