revert no-longer-needed

Author: jbrockmendel

pandas/tests/reductions/test_stat_reductions.py

@@ -74,8 +74,8 @@ def test_td64_mean(self, box):
         obj = box(tdarr)
 
         result = obj.mean()
-        np_tda = np.array(tdarr)
-        assert result == np_tda.mean()
+        expected = np.array(tdarr).mean()
+        assert result == expected
 
         tdarr[0] = pd.NaT
         assert obj.mean(skipna=False) is pd.NaT