Issue #3440115 by mondrake: Change remaining File module test dataproviders to static

core/modules/file/tests/src/Functional/Formatter/FileMediaFormatterTestBase.php

@@ -86,7 +86,7 @@ protected function createMediaField($formatter, $file_extensions, array $formatt
    *     - The number of expected HTML tags.
    *     - An array of settings for the field formatter.
    */
-  public function dataProvider() {
+  public static function dataProvider(): array {
     return [
       [2, []],
       [1, ['multiple_file_display_type' => 'sources']],