Issue #3065465 by heddn: Modified code doesn't check core correctly

ReadinessCheckers/ModifiedFiles.php

@@ -34,7 +34,13 @@ class ModifiedFiles implements ReadinessCheckerInterface {
    */
   protected static function getInfos() {
     $extensions = drupal_system_listing('/^' . DRUPAL_PHP_FUNCTION_PATTERN . '\.info$/', 'modules', $key = 'name', $min_depth = 1);
-    return array_merge($extensions, drupal_system_listing('/^' . DRUPAL_PHP_FUNCTION_PATTERN . '\.info$/', 'themes', $key = 'name', $min_depth = 1));
+    $infos = array_merge($extensions, drupal_system_listing('/^' . DRUPAL_PHP_FUNCTION_PATTERN . '\.info$/', 'themes', $key = 'name', $min_depth = 1));
+    $system = $infos['system'];
+    $infos = array_filter($infos, function($info) {
+      return substr($info->uri, 0, 7) !== "modules" && substr($info->uri, 0, 6) !== "themes";
+    });
+    $infos['drupal']  = $system;
+    return $infos;
   }
 
 }