Delete references to github.com/tensorflow/models/blob/master/tutorials
Delete references to github.com/tensorflow/models/blob/master/tutorials

The directory is not maintained, and is no longer being used for tensorflow.org.

I am deleting it in https://github.com/tensorflow/models/pull/8276

PiperOrigin-RevId: 302583413

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