Unsupported output type of N11onnxruntime22SequenceTensorTypeBaseE. Can't constant fold SequenceEmpty node 'SequenceEmpty_5330'
## Environment
- `transformers` version:4.16.0.dev0
- Platform:centos7
- Python version:3.6.5
- PyTorch version (GPU?):1.10.1
- CUDA:10.2
- Cudnn:7.65

Models:

- T5, BART, Marian, Pegasus, EncoderDecoder: @patrickvonplaten

Library:

- Text generation: @patrickvonplaten @narsil


## Information

The problem arises when using:
* [[ ] the official example scripts: (give details below)](https://github.com/huggingface/transformers/tree/v4.15.0/examples/onnx/pytorch/summarization)

## Add
Thank you very much for your open source code! I encountered the following problems when using the official code to convert BART into onnx model. 

Debug info:
2022-01-28 15:48:27.150774771 [W:onnxruntime:, graph.cc:3526 CleanUnusedInitializersAndNodeArgs] Removing initializer '1751'. It is not used by any node and should be removed from the model.
2022-01-28 15:48:27.309347842 [W:onnxruntime:, graph.cc:3526 CleanUnusedInitializersAndNodeArgs] Removing initializer '5836'. It is not used by any node and should be removed from the model.
2022-01-28 15:48:27.309405007 [W:onnxruntime:, graph.cc:3526 CleanUnusedInitializersAndNodeArgs] Removing initializer '5882'. It is not used by any node and should be removed from the model.
2022-01-28 15:48:27.309424807 [W:onnxruntime:, graph.cc:3526 CleanUnusedInitializersAndNodeArgs] Removing initializer '5790'. It is not used by any node and should be removed from the model.
2022-01-28 15:48:27.322407481 [W:onnxruntime:, constant_folding.cc:202 ApplyImpl] Unsupported output type of N11onnxruntime22SequenceTensorTypeBaseE. Can't constant fold SequenceEmpty node 'SequenceEmpty_5330'
2022-01-28 15:48:27.322776093 [W:onnxruntime:, constant_folding.cc:202 ApplyImpl] Unsupported output type of N11onnxruntime22SequenceTensorTypeBaseE. Can't constant fold SequenceEmpty node 'SequenceEmpty_808'
2022-01-28 15:48:27.322825883 [W:onnxruntime:, constant_folding.cc:202 ApplyImpl] Unsupported output type of N11onnxruntime22SequenceTensorTypeBaseE. Can't constant fold SequenceEmpty node 'SequenceEmpty_1'
2022-01-28 15:48:27.326471594 [W:onnxruntime:, constant_folding.cc:202 ApplyImpl] Unsupported output type of N11onnxruntime22SequenceTensorTypeBaseE. Can't constant fold SequenceEmpty node 'SequenceEmpty_5128'
2022-01-28 15:48:27.362769188 [W:onnxruntime:, constant_folding.cc:202 ApplyImpl] Unsupported output type of N11onnxruntime22SequenceTensorTypeBaseE. Can't constant fold SequenceEmpty node 'SequenceEmpty_5330'
2022-01-28 15:48:27.363078495 [W:onnxruntime:, constant_folding.cc:202 ApplyImpl] Unsupported output type of N11onnxruntime22SequenceTensorTypeBaseE. Can't constant fold SequenceEmpty node 'SequenceEmpty_808'
2022-01-28 15:48:27.363121543 [W:onnxruntime:, constant_folding.cc:202 ApplyImpl] Unsupported output type of N11onnxruntime22SequenceTensorTypeBaseE. Can't constant fold SequenceEmpty node 'SequenceEmpty_1'
2022-01-28 15:48:27.366445273 [W:onnxruntime:, constant_folding.cc:202 ApplyImpl] Unsupported output type of N11onnxruntime22SequenceTensorTypeBaseE. Can't constant fold SequenceEmpty node 'SequenceEmpty_5128'
2022-01-28 15:48:27.429176464 [W:onnxruntime:, constant_folding.cc:202 ApplyImpl] Unsupported output type of N11onnxruntime22SequenceTensorTypeBaseE. Can't constant fold SequenceEmpty node 'SequenceEmpty_5330'
2022-01-28 15:48:27.429415152 [W:onnxruntime:, constant_folding.cc:202 ApplyImpl] Unsupported output type of N11onnxruntime22SequenceTensorTypeBaseE. Can't constant fold SequenceEmpty node 'SequenceEmpty_808'
2022-01-28 15:48:27.429447650 [W:onnxruntime:, constant_folding.cc:202 ApplyImpl] Unsupported output type of N11onnxruntime22SequenceTensorTypeBaseE. Can't constant fold SequenceEmpty node 'SequenceEmpty_1'
2022-01-28 15:48:27.431914509 [W:onnxruntime:, constant_folding.cc:202 ApplyImpl] Unsupported output type of N11onnxruntime22SequenceTensorTypeBaseE. Can't constant fold SequenceEmpty node 'SequenceEmpty_5128'
2022-01-28 15:48:27.570257513 [W:onnxruntime:, graph.cc:3526 CleanUnusedInitializersAndNodeArgs] Removing initializer '5152'. It is not used by any node and should be removed from the model.
2022-01-28 15:48:27.570293380 [W:onnxruntime:, graph.cc:3526 CleanUnusedInitializersAndNodeArgs] Removing initializer '5149'. It is not used by any node and should be removed from the model.




Pinging @mfuntowicz for the onnx export.<|||||>Add
This error runs fine under onnxruntime, but when deployed to Tensorrt, it will not paser onnx model<|||||>This issue has been automatically marked as stale because it has not had recent activity. If you think this still needs to be addressed please comment on this thread.

Please note that issues that do not follow the [contributing guidelines](https://github.com/huggingface/transformers/blob/master/CONTRIBUTING.md) are likely to be ignored.