Let all TestRmtree tests run on 3.7

They are no longer using TemporaryDirectory (because they use the
pytest tmp_path fixture instead), so the limitations of
TemporaryDirectory on Python 3.7 are no longer relevant.

Author: EliahKagan

Diff for: test/test_util.py

@@ -106,10 +106,6 @@ def test_deletes_dir_with_readonly_files(self, tmp_path):
         sys.platform == "cygwin",
         reason="Cygwin can't set the permissions that make the test meaningful.",
     )
-    @pytest.mark.skipif(
-        sys.version_info < (3, 8),
-        reason="In 3.7, TemporaryDirectory doesn't clean up after weird permissions.",
-    )
     def test_wraps_perm_error_if_enabled(self, mocker, permission_error_tmpdir):
         """rmtree wraps PermissionError when HIDE_WINDOWS_KNOWN_ERRORS is true."""
         # Access the module through sys.modules so it is unambiguous which module's
@@ -129,10 +125,6 @@ def test_wraps_perm_error_if_enabled(self, mocker, permission_error_tmpdir):
         sys.platform == "cygwin",
         reason="Cygwin can't set the permissions that make the test meaningful.",
     )
-    @pytest.mark.skipif(
-        sys.version_info < (3, 8),
-        reason="In 3.7, TemporaryDirectory doesn't clean up after weird permissions.",
-    )
     def test_does_not_wrap_perm_error_unless_enabled(self, mocker, permission_error_tmpdir):
         """rmtree does not wrap PermissionError when HIDE_WINDOWS_KNOWN_ERRORS is false."""
         # See comments in test_wraps_perm_error_if_enabled for details about patching.