Introduces fixes to get VQ-VAE working.
Introduces fixes to get VQ-VAE working.

PiperOrigin-RevId: 180425931

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