remove empty lines in thread.c

src/threads/thread.c

@@ -291,7 +291,6 @@ thread_unblock (struct thread *t)
   old_level = intr_disable ();
   ASSERT (t->status == THREAD_BLOCKED);
 
-
   /* Insert the thread back into the ready list in priority order. */
   list_insert_ordered(&ready_list, &t->elem, priority_more, NULL);
 
@@ -367,10 +366,8 @@ thread_yield (void)
 
   if (cur != idle_thread)
     {
-
       /* Insert the thread back into the ready list in priority order. */
       list_insert_ordered(&ready_list, &cur->elem, priority_more, NULL);
-
     }
 
   cur->status = THREAD_READY;
@@ -402,7 +399,6 @@ bool
 priority_more (const struct list_elem *a_, const struct list_elem *b_,
                void *aux UNUSED)
 {
-
   struct thread *a = list_entry (a_, struct thread, elem);
   struct thread *b = list_entry (b_, struct thread, elem);