Fix BigBirdModelTester (#16310)

* fix

* update the expected value in test_fast_integration

Co-authored-by: ydshieh <ydshieh@users.noreply.github.com>

tests/big_bird/test_modeling_big_bird.py

@@ -70,7 +70,7 @@ class BigBirdModelTester:
         attention_type="block_sparse",
         use_bias=True,
         rescale_embeddings=False,
-        block_size=16,
+        block_size=8,
         num_rand_blocks=3,
         position_embedding_type="absolute",
         scope=None,
@@ -581,7 +581,7 @@ class BigBirdModelTest(ModelTesterMixin, unittest.TestCase):
             self.assertTrue(
                 torch.allclose(
                     hidden_states[0, 0, :5],
-                    torch.tensor([1.4943, 0.0928, 0.8254, -0.2816, -0.9788], device=torch_device),
+                    torch.tensor([1.4825, 0.0774, 0.8226, -0.2962, -0.9593], device=torch_device),
                     atol=1e-3,
                 )
             )