MAINT: Remove duplicate Series sort_index check

Duplicate boolean validation check for sort_index in series/test_validate.py

Author: gfyoung

pandas/tests/series/test_validate.py

@@ -23,9 +23,6 @@ def test_validate_bool_args(self):
             with pytest.raises(ValueError):
                 self.s.sort_index(inplace=value)
 
-            with pytest.raises(ValueError):
-                self.s.sort_index(inplace=value)
-
             with pytest.raises(ValueError):
                 self.s.rename(inplace=value)