message: Aligh atol with test_autocast in bf16
diff: @@ -978,8 +978,9 @@ class TestPrepackCases(TestCase):
  rtol=1e-5
  atol=1e-5
  if dtype == torch.bfloat16:
  + # align atol with that in _test_lstm in test_autocast.py of bf16
  rtol=2e-2
  - atol=2e-2
  + atol=3e-2
  x = input.to(dtype=dtype).float()
  h = h.to(dtype=dtype).float()
  c = c.to(dtype=dtype).float()
  