Added TEST shard to the dataset split. Data generator will now create
Added TEST shard to the dataset split. Data generator will now create

PiperOrigin-RevId: 205154358

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