🐛 Bug

I get the same error when I try to convert pytorch int8 maxpool to onnx to c2.

To Reproduce

Steps to reproduce the behavior:

1. I run torch2onnx_maxpool.py(the code list bellow) to get onnx and get this warning:
   "symbolic_helper.py:176: UserWarning: ONNX export failed on max_pool2d because input size not accessible not supported"

2. when I run run_onnx_maxpool.py to load onnx model, I get this error
   "Exception: Don't know how to translate op max_pool2d"

What should I do? The code is here
https://github.com/boydyang1/test_pytorch_int8_maxpool/blob/master/torch2onnx_maxpool.py
https://github.com/boydyang1/test_pytorch_int8_maxpool/blob/master/run_onnx_maxpool.py
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