Add Notebook for Bert Model exported by Keras2onnx (#3271)
* Add notebook for bert squad model exported by python 1.4
* update bert performance test tool:
(1) set OpenMP environment variable before importing onnxruntime.
(2) launch new process for each test.
* Add notebook
Reduce combinations in perf test
* update readme
* fix quote
* Allow test multiple batch_size
* Add latency percentile
* Add warm up run
Reset logger for notebook
* refine default settings to test for cpu/gpu
* Add script to dump machine info
* Add notebooks for PyTorch SQuAD model GPU and CPU inference
* Update machineinfo.py: add license header; format by yapf
* Do not reset log handler. Skip adding handler if existed.
* Add comments about GPU result diff.
Filter rows of batch set to keep only one setting.
* update according to review feedback
* Download script from master branch
* Add notebook for bert model exported by keras2onnx
* format columns in result table
* re-run and update notebook
