Backport PR #60703 on branch 2.3.x (TST(string dtype): Resolve xfails in stack_unstack) (#60706)

Backport PR #60703: TST(string dtype): Resolve xfails in stack_unstack

Co-authored-by: Richard Shadrach <[email protected]>

Author: meeseeksmachine

pandas/tests/frame/test_stack_unstack.py

@@ -5,8 +5,6 @@
 import numpy as np
 import pytest
 
-from pandas._config import using_string_dtype
-
 from pandas._libs import lib
 from pandas.errors import PerformanceWarning
 
@@ -1652,7 +1650,6 @@ def test_unstack_multiple_no_empty_columns(self):
         expected = unstacked.dropna(axis=1, how="all")
         tm.assert_frame_equal(unstacked, expected)
 
-    @pytest.mark.xfail(using_string_dtype(), reason="TODO(infer_string)", strict=False)
     @pytest.mark.filterwarnings(
         "ignore:The previous implementation of stack is deprecated"
     )
@@ -1896,7 +1893,6 @@ def test_stack_level_name(self, multiindex_dataframe_random_data, future_stack):
         expected = frame.stack(future_stack=future_stack)
         tm.assert_series_equal(result, expected)
 
-    @pytest.mark.xfail(using_string_dtype(), reason="TODO(infer_string)", strict=False)
     @pytest.mark.filterwarnings(
         "ignore:The previous implementation of stack is deprecated"
     )