MDL-81632 block_recentlyaccesseditems: deterministic item ordering.

Behat tests of this functionality could trigger the unlikely (in real
world usage) scenario where a user has an identical "timeaccess" value
for multiple course activities.

This led to random failures in said tests when the DB ordered items in
apparently random order, where the "timeaccess" value was equal.

blocks/recentlyaccesseditems/classes/helper.php

@@ -58,7 +58,7 @@ class helper {
                   FROM {block_recentlyaccesseditems} rai
                   JOIN {course} c ON c.id = rai.courseid
                  WHERE userid = :userid
-                 ORDER BY rai.timeaccess DESC";
+              ORDER BY rai.timeaccess DESC, rai.id DESC";
         $records = $DB->get_records_sql($sql, $paramsql);
         $order = 0;