MDL-74255 quiz: clean up lots of stuff mainly in the tests

This fixes lots of stuff like outdated or incomplete PHPdoc comments
or test heler functions where the arguments don't have their types
declared.

A few more significant fixes, like places were a silly method
was used to get a context which was readily available.

question/type/questiontypebase.php

@@ -903,7 +903,7 @@ class question_type {
      *                         specific information (it is passed by reference).
      */
     public function get_question_options($question) {
-        global $CFG, $DB, $OUTPUT;
+        global $DB, $OUTPUT;
 
         if (!isset($question->options)) {
             $question->options = new stdClass();