Refining the cycle loss function, and removed redundant gradient tape
Refining the cycle loss function, and removed redundant gradient tape

- Separating the cycle loss for F(G(x)) and G(F(y)) results in the
gradient not calculated on the loss of G(F(y)) with respect to G, and
loss of F(G(x)) with respect to F.

- Redundant gradient tape is removed since persistent is already set to
true.

tensorflow/docs,tensorflow/docs,tensorflow/docs