Generate: delete unused TF _reorder_cache (#20964)

templates/adding_a_new_model/cookiecutter-template-{{cookiecutter.modelname}}/modeling_tf_{{cookiecutter.lowercase_modelname}}.py

@@ -3028,13 +3028,6 @@ class TF{{cookiecutter.camelcase_modelname}}ForConditionalGeneration(TF{{cookiec
             "use_cache": use_cache,  # change this to avoid caching (presumably for debugging)
         }
 
-    @staticmethod
-    def _reorder_cache(past, beam_idx):
-        reordered_past = ()
-        for layer_past in past:
-            reordered_past += (tuple(tf.gather(past_state, beam_idx, axis=0) for past_state in layer_past),)
-        return reordered_past
-
     def hf_compute_loss(self, labels, logits):
         """CrossEntropyLoss that ignores pad tokens"""
         loss_fn = tf.keras.losses.SparseCategoricalCrossentropy(