Fixed "KeyError: 'inputs'" by redirecting 'inputs' to 'targets' in estimator_model_fn when use_tpu is used.
Fixed "KeyError: 'inputs'" by redirecting 'inputs' to 'targets' in estimator_model_fn when use_tpu is used.

PiperOrigin-RevId: 237492137

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