TST: xfail mpl 2.2 tests

xref pandas-dev#20031

Author: jreback

pandas/tests/plotting/test_datetimelike.py

@@ -1041,6 +1041,7 @@ def test_irreg_dtypes(self):
         _, ax = self.plt.subplots()
         _check_plot_works(df.plot, ax=ax)
 
+    @td.xfail_if_mpl_2_2
     @pytest.mark.slow
     def test_time(self):
         t = datetime(1, 1, 1, 3, 30, 0)