Fix checkfail in tf.raw_ops.Substr
This is being rolled back. We need a different fix Let's try again with `>= 0` instead of `> 0`
The API `tf.raw_ops.Substr`  currently validates whether the input args `pos` and `len` are of same shape or not.Its not checking whether these tensors are empty or not and trying to access the Tensor values directly without validating.If a user passes empty tensors it will lead to` assertion failure` causing core dumped error.

May fixes #63036