Issue #2078007 by plopesc: Modernize simpletest.module forms.

core/modules/simpletest/lib/Drupal/simpletest/Form/SimpletestTestForm.php

@@ -93,12 +93,6 @@ public function buildForm(array $form, array &$form_state) {
     return $form;
   }
 
-  /**
-   * {@inheritdoc}
-   */
-  public function validateForm(array &$form, array &$form_state) {
-  }
-
   /**
    * {@inheritdoc}
    */