Goal:
  
  A : Type
  H : ReflectEq A
  l1 : list A
  l2 : list A
  l : list A
  ll1 : is_prefix (rev l) (rev l1)
  ll2 : is_prefix (rev l) (rev l2)
  ============================
   (is_prefix (rev l) (fst (fst (split_prefix (rev l1) (rev l2))))
    → is_prefix (rev l) (rev (snd (split_suffix l1 l2))))


DEBUG:Going to execute:
unfold split_suffix
DEBUG LTAC Evaluated term: z