maintenance: add trace2 regions for task execution

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/gc.c

@@ -927,10 +927,12 @@ static int maintenance_run_tasks(struct maintenance_run_opts *opts)
 		     !tasks[i].auto_condition()))
 			continue;
 
+		trace2_region_enter("maintenance", tasks[i].name, r);
 		if (tasks[i].fn(opts)) {
 			error(_("task '%s' failed"), tasks[i].name);
 			result = 1;
 		}
+		trace2_region_leave("maintenance", tasks[i].name, r);
 	}
 
 	rollback_lock_file(&lk);