Fix pretrained=True for test_pt_onnx_trt (#67818)
Summary:
Addresses https://github.com/pytorch/pytorch/pull/66312#issuecomment-960357403
Pull Request resolved: https://github.com/pytorch/pytorch/pull/67818
Reviewed By: malfet
Differential Revision: D32161208
Pulled By: janeyx99
fbshipit-source-id: 076e52ddc8718c74eb2941e867d92bfa4fe70f80
