remove unnecessary code

Author: sycai

tests/unit/core/test_blocks.py

@@ -96,14 +96,6 @@ def test_block_from_local(data):
 
 def test_block_to_pandas_dry_run__raises_error_when_sampling_is_enabled():
     mock_session = mock.create_autospec(spec=bigframes.Session)
-    mock_executor = mock.create_autospec(
-        spec=bigframes.session.executor.BigQueryCachingExecutor
-    )
-
-    # hard-coded the returned dimension of the session for that each of the test case contains 3 rows.
-    mock_session._executor = mock_executor
-    mock_executor.get_row_count.return_value = 3
-
     block = blocks.Block.from_local(pandas.DataFrame(), mock_session)
 
     with pytest.raises(NotImplementedError):