MDL-59487 task: Add run again button.

Co-authored-by: Brendan Heywood <[email protected]>

admin/tool/task/schedule_task.php

@@ -92,6 +92,11 @@ $CFG->mtrace_wrapper = 'tool_task_mtrace_wrapper';
 echo html_writer::end_tag('pre');
 
 $output = $PAGE->get_renderer('tool_task');
+
+// Re-run the specified task (this will output an error if it doesn't exist).
+echo $OUTPUT->single_button(new moodle_url('/admin/tool/task/schedule_task.php',
+        array('task' => $taskname, 'confirm' => 1, 'sesskey' => sesskey())),
+        get_string('runagain', 'tool_task'));
 echo $output->link_back();
 
 echo $OUTPUT->footer();