Bug 39746 Move super class constructor combo up.
Move the combo selection for the super class constructors to be above the field treeviewer for the "Create constructor using fields" source action.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/actions/CreateNewConstructorAction.java
/*
	 * Returns fields in the selection or <code>null</code> if the selection is 
	 * empty or not valid.
	 */
	private IField[] getSelectedFields(IStructuredSelection selection) {
		List elements= selection.toList();
		int nElements= elements.size();
		if (nElements > 0) {
			IField[] res= new IField[nElements];
			ICompilationUnit cu= null;
			for (int i= 0; i < nElements; i++) {
				Object curr= elements.get(i);
				if (curr instanceof IField) {
					IField fld= (IField)curr;
					
					if (i == 0) {
						
						cu= fld.getCompilationUnit();
						if (cu == null) {
							return null;
						}
					} else if (!cu.equals(fld.getCompilationUnit())) {
						
						return null;
					}
					try {
						if (fld.getDeclaringType().isInterface()) {
							
							return null;
						}