CI: Remove xfail for xpassing test for Python 3.8 (#42558)

Author: lithomas1

pandas/tests/scalar/timedelta/test_arithmetic.py

@@ -10,15 +10,13 @@
 import numpy as np
 import pytest
 
-from pandas.compat import is_numpy_dev
 from pandas.errors import OutOfBoundsTimedelta
 
 import pandas as pd
 from pandas import (
     NaT,
     Timedelta,
     Timestamp,
-    compat,
     offsets,
 )
 import pandas._testing as tm
@@ -434,15 +432,7 @@ def test_td_div_numeric_scalar(self):
         "nan",
         [
             np.nan,
-            pytest.param(
-                np.float64("NaN"),
-                marks=pytest.mark.xfail(
-                    # Works on numpy dev only in python 3.9
-                    is_numpy_dev and not compat.PY39,
-                    raises=RuntimeWarning,
-                    reason="https://github.com/pandas-dev/pandas/issues/31992",
-                ),
-            ),
+            np.float64("NaN"),
             float("nan"),
         ],
     )