bpo-41069: Make TESTFN and the CWD for tests containing non-ascii characters. (GH-21035)

diff --git a/Lib/test/test_genericpath.py b/Lib/test/test_genericpath.py
index 9d5ac44..e7acbcd 100644
--- a/Lib/test/test_genericpath.py
+++ b/Lib/test/test_genericpath.py
@@ -534,7 +534,7 @@
 class PathLikeTests(unittest.TestCase):
 
     def setUp(self):
-        self.file_name = support.TESTFN.lower()
+        self.file_name = support.TESTFN
         self.file_path = FakePath(support.TESTFN)
         self.addCleanup(support.unlink, self.file_name)
         create_file(self.file_name, b"test_genericpath.PathLikeTests")