Use session in cyclegan_upsample tests.
Use session in cyclegan_upsample tests.

PiperOrigin-RevId: 206182864

tensorflow/tensor2tensor,vthorsteinsson/tensor2tensor,tensorflow/tensor2tensor,vthorsteinsson/tensor2tensor,vthorsteinsson/tensor2tensor,tensorflow/tensor2tensor,tensorflow/tensor2tensor,vthorsteinsson/tensor2tensor,tensorflow/tensor2tensor