Author: Mathew May
MDL-76134 gradebook: Add a bare dropdown component
http://git.moodle.org/gw?p=moodle.git;a=commit;h=6b0d3b3eae121c331855dcfee76f61fd41d58d06
http://github.com/moodle/moodle/commit/6b0d3b3eae121c331855dcfee76f61fd41d58d06
+ 4.2 en [aria-toggledropdown,core_grades]