Remove slow tag from notebook test for PR testing.

Author: smburdick

Diff for: dev_tools/notebooks/notebook_test.py

@@ -86,7 +86,6 @@ def env_with_temporary_pip_target():
         yield env
 
 
-@pytest.mark.slow
 @pytest.mark.skipif(sys.platform not in ["linux", "darwin"], reason="Linux/Mac-only test")
 @pytest.mark.parametrize("notebook_path", filter_notebooks(list_all_notebooks(), SKIP_NOTEBOOKS))
 def test_notebooks_against_cirq_head(