sort bundles in config:dump-reference command

This backports #17495 to the `2.3` branch.

src/Symfony/Bundle/FrameworkBundle/Command/ConfigDumpReferenceCommand.php

@@ -66,6 +66,11 @@ EOF
 
         if (empty($name)) {
             $output->writeln('Available registered bundles with their extension alias if available:');
+
+            usort($bundles, function($bundleA, $bundleB) {
+                return strcmp($bundleA->getName(), $bundleB->getName());
+            });
+
             foreach ($bundles as $bundle) {
                 $extension = $bundle->getContainerExtension();
                 $output->writeln($bundle->getName().($extension ? ': '.$extension->getAlias() : ''));