MDL-81521 core: Update all possibly data providers to be static

Note: Some data providers could not be automatically be converted to
being static. These will be handled in a separate issue.

auth/ldap/tests/plugin_test.php

@@ -45,7 +45,7 @@ class plugin_test extends \advanced_testcase {
      *
      * @return array[]
      */
-    public function auth_ldap_provider() {
+    public static function auth_ldap_provider(): array {
         $pagesizes = [1, 3, 5, 1000];
         $subcontexts = [0, 1];
         $combinations = [];