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.

lib/phpunit/tests/util_test.php

@@ -36,7 +36,7 @@ class util_test extends \advanced_testcase {
         }
     }
 
-    public function set_table_modified_by_sql_provider() {
+    public static function set_table_modified_by_sql_provider(): array {
         global $DB;
         $prefix = $DB->get_prefix();