fix converter test error (#3083)

Author: lanluo-nvidia

tests/py/dynamo/conversion/test_argmin_aten.py

@@ -2,6 +2,7 @@
 import torch.nn as nn
 from parameterized import parameterized
 from torch.testing._internal.common_utils import run_tests
+from torch_tensorrt import Input
 
 from .harness import DispatchTestCase