job control: Small reorganization of wait_consider_task()

Move EXIT_DEAD test in wait_consider_task() above ptrace check.  As
ptraced tasks can't be EXIT_DEAD, this change doesn't cause any
behavior change.  This is to prepare for further changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>

kernel/exit.c

@@ -1537,6 +1537,10 @@ static int wait_consider_task(struct wait_opts *wo, int ptrace,
 		return 0;
 	}
 
+	/* dead body doesn't have much to contribute */
+	if (p->exit_state == EXIT_DEAD)
+		return 0;
+
 	if (likely(!ptrace) && unlikely(task_ptrace(p))) {
 		/*
 		 * This child is hidden by ptrace.
@@ -1546,9 +1550,6 @@ static int wait_consider_task(struct wait_opts *wo, int ptrace,
 		return 0;
 	}
 
-	if (p->exit_state == EXIT_DEAD)
-		return 0;
-
 	/*
 	 * We don't reap group leaders with subthreads.
 	 */