Fix #10258 - clean up resource warning

Lib/test/test_tokenize.py

@@ -590,7 +590,9 @@ def roundtrip(f):
     """
     if isinstance(f, str):
         f = BytesIO(f.encode('utf-8'))
+    try:
         token_list = list(tokenize(f.readline))
+    finally:
         f.close()
     tokens1 = [tok[:2] for tok in token_list]
     new_bytes = untokenize(tokens1)