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
if (checkedElements == null)
				return;
			ArrayList result= new ArrayList(checkedElements.length);
			for (int i= 0; i < checkedElements.length; i++) {
				Object curr= checkedElements[i];
				if (curr instanceof IField) {
					result.add(curr);
				}
			}
						
			selected= (IField[]) result.toArray(new IField[result.size()]);
			
			CodeGenerationSettings settings= JavaPreferencesSettings.getCodeGenerationSettings();
			settings.createComments= dialog.getGenerateComment();
	
			IJavaElement elementPosition= dialog.getElementPosition();
			int superIndex= dialog.getSuperIndex();
			AddCustomConstructorOperation op= new AddCustomConstructorOperation(type, settings, selected, false, elementPosition, superIndex);
			IRewriteTarget target= editor != null ? (IRewriteTarget) editor.getAdapter(IRewriteTarget.class) : null;
			if (target != null) {
				target.beginCompoundChange();		
			}
			try {
				IRunnableContext context= JavaPlugin.getActiveWorkbenchWindow();
				if (context == null) {
					context= new BusyIndicatorRunnableContext();
				}				
				context.run(false, true, new WorkbenchRunnableAdapter(op));
				IMethod res= op.getCreatedConstructor();
				if (res.getCompilationUnit().isWorkingCopy())  {