Using the same list of tensors to represent different lists in keras models

[khatchad]

We should have a seperate list for each of these attributes.

https://github.com/wala/ML/blob/16acfbcf22c66a220176c1b95d30e7026c7231b2/com.ibm.wala.cast.python.ml/data/tensorflow.xml#L749-L755