[python API]add batchSize support in model.predict (#2518)
[python API]add batchSize support in model.predict (#2518)

* add batchSize for predict

* meet code review

* meet code review

* fix space

* fix ut

intel-analytics/BigDL,yangw1234/BigDL,intel-analytics/BigDL,intel-analytics/BigDL,yangw1234/BigDL,yangw1234/BigDL,yangw1234/BigDL,intel-analytics/BigDL