Make Transformers use cache files when hf.co is down (#16362)

* Make Transformers use cache files when hf.co is down

* Fix tests

* Was there a random circleCI failure?

* Isolate patches

* Style

* Comment out the failure since it doesn't fail anymore

* Better comment

tests/utils/test_offline.py

@@ -59,10 +59,10 @@ socket.socket = offline_socket
         # next emulate no network
         cmd = [sys.executable, "-c", "\n".join([load, mock, run])]
 
-        # should normally fail as it will fail to lookup the model files w/o the network
-        env["TRANSFORMERS_OFFLINE"] = "0"
-        result = subprocess.run(cmd, env=env, check=False, capture_output=True)
-        self.assertEqual(result.returncode, 1, result.stderr)
+        # Doesn't fail anymore since the model is in the cache due to other tests, so commenting this.
+        # env["TRANSFORMERS_OFFLINE"] = "0"
+        # result = subprocess.run(cmd, env=env, check=False, capture_output=True)
+        # self.assertEqual(result.returncode, 1, result.stderr)
 
         # should succeed as TRANSFORMERS_OFFLINE=1 tells it to use local files
         env["TRANSFORMERS_OFFLINE"] = "1"