Replaced method for listing directories files with a simpler one.

Author: freskoulix

tests/compile_tester/test_compile_tester_projects.py

@@ -31,7 +31,7 @@ def test_compile_local_files(self, tester_login):
         """Tests that we can upload all of cb_compile_tester's projects
         (stored locally in test_data/cb_compile_tester), compile them,
         and finally delete them."""
-        filenames = next(os.walk(COMPILE_TESTER_DIR))[2]
+        filenames = os.listdir(COMPILE_TESTER_DIR)
         test_files = [os.path.join(COMPILE_TESTER_DIR, name) for name in filenames]
         projects = [self.upload_project('#uploadFolderZip form', fname,
             os.path.splitext(os.path.basename(fname))[0]) for fname