test_os: add TemporaryFileTests to the testcase list

The testcase was never executed, it's now fixed.
diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
index af02939..0866593 100644
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -1344,6 +1344,7 @@
         PidTests,
         LoginTests,
         LinkTests,
+        TemporaryFileTests,
     )
 
 if __name__ == "__main__":