[Bug] [Relay] Error when compiling a simple ONNX model with Abs and PRelu

[luyaor]

Description

When compiling following model with TVM, it will error.

The model(with ONNX as frontend) with error is as follows, check bug.onnx in bug3.zip

Error Log

Traceback (most recent call last):
  File "check.py", line 11, in <module>
    mod, params = relay.frontend.from_onnx(onnx_model, {})
  File "/Users/luyaor/Documents/tvm/python/tvm/relay/frontend/onnx.py", line 2806, in from_onnx
    mod, params = g.from_onnx(graph, opset, freeze_params)
  File "/Users/luyaor/Documents/tvm/python/tvm/relay/frontend/onnx.py", line 2613, in from_onnx
    op = self._convert_operator(op_name, inputs, attr, opset)
  File "/Users/luyaor/Documents/tvm/python/tvm/relay/frontend/onnx.py", line 2721, in _convert_operator
    sym = convert_map[op_name](inputs, attrs, self._params)
  File "/Users/luyaor/Documents/tvm/python/tvm/relay/frontend/onnx.py", line 820, in _impl_v1
    input_channels = infer_shape(inputs[0])[1]
IndexError: tuple index out of range

How to reproduce

Environment

Python3, with tvm, onnx

tvm version: c31e338 Wed Dec 9 14:52:58 2020 +0900

1. Download bug3.zip

2. Run python check.py.

[jwfromm]

This bug is also fixed in #7208 and was caused by the same issue as #7202.