Skip unicode test in C locale

Closes gh-10780

IPython/utils/tests/test_path.py

@@ -394,6 +394,7 b' def test_unescape_glob():'
     nt.assert_equal(path.unescape_glob(r'\a'), r'\a')
 
 
+@onlyif_unicode_paths
 def test_ensure_dir_exists():
     with TemporaryDirectory() as td:
         d = os.path.join(td, '∂ir')