moodlelib:remove_course_contents() does not need to 'clearcache'

Now that delete_context() marks things dirty, we no longer
need to clearcache. Which is deprecated anyway.

lib/moodlelib.php

@@ -3355,11 +3355,6 @@ function remove_course_contents($courseid, $showfeedback=true) {
         delete_context(CONTEXT_COURSE, $course->id);
     }
 
-    // fix for MDL-9016
-    // clear the cache because the course context is deleted, and
-    // we don't want to write assignment, overrides and context_rel table
-    // with this old context id!
-    get_context_instance('clearcache');
     return $result;
 }