new example for ut:test_autoestimator_pytorch (#3834)
new example for ut:test_autoestimator_pytorch (#3834)

* create new example for ut

* add four argparse and mse,such as loss,num_samples,optimizer,training_iteration,best_model_mse

* use accuracy instead of mse,remove dict.get method,delete "return best_model".

* Solve the proposed needs, except for remove "all_available_features"

* remove all_available_features

* remove multioutput="raw_values",add auto test fot the example

* for jenkins.

* remove redundant symbols in ln[144]

* autopep8
yangw1234/BigDL,intel-analytics/BigDL,yangw1234/BigDL,intel-analytics/BigDL,yangw1234/BigDL,intel-analytics/BigDL,intel-analytics/BigDL,yangw1234/BigDL