Created by: wanghaoshuang

Make ocr model support for variable height.

Check done:

• Training with DATA_SHAPE = [1, 40, 512] and input.height=48
• Infer&Test with DATA_SHAPE = [1, 40, 512] and input.height=40
• Infer&Test with DATA_SHAPE = [1, 40, 512] and input.height=60