Performance issue in the definition of free_form_mask_tf, tensorflow/net/ops.py(P1)

[DLPerf]

Hello, I found a performance issue in the definition of free_form_mask_tf, tensorflow/net/ops.py, tf.py_func and tf.reshape will be created repeatedly during program execution, resulting in reduced efficiency. I think p should be created before the loop.

Looking forward to your reply. Btw, I am very glad to create a PR to fix it if you are too busy.

[shepnerd]

Thank you for your issue. It will be great if you can share your improved version.