Update serving code to enable saved_model=True (#18153)

* Add serving_output and serving methods to some vision models

* Add serving outputs for DeiT

* Don't convert hidden states - differing shapes

* Make saveable

* Fix up

* Make swin saveable

* Add in tests

* Fix funnel tests (can't convert to tensor)

* Fix numpy call

* Tidy up a bit

* Add in hidden states - resnet

* Remove numpy

* Fix failing tests - tensor shape and skipping tests

* Remove duplicated function

* PR comments - formatting and var names

* PR comments
Add suggestions made by Joao Gante:
* Use tf.shape instead of shape_list
* Use @tooslow decorator on tests
* Simplify some of the logic

* PR comments
Address Yih-Dar Sheih comments - making tensor names consistent and make types float

* Types consistent with docs; disable test on swin (slow)

* CI trigger

* Change input_features to float32

* Add serving_output for segformer

* Fixup

Co-authored-by: Amy Roberts <amyeroberts@users.noreply.github.com>

tests/models/marian/test_modeling_tf_marian.py

@@ -19,7 +19,7 @@ import unittest
 import warnings
 
 from transformers import AutoTokenizer, MarianConfig, MarianTokenizer, TranslationPipeline, is_tf_available
-from transformers.testing_utils import require_sentencepiece, require_tf, require_tokenizers, slow
+from transformers.testing_utils import require_sentencepiece, require_tf, require_tokenizers, slow, tooslow
 from transformers.utils import cached_property
 
 from ...test_configuration_common import ConfigTester
@@ -246,8 +246,8 @@ class TFMarianModelTest(TFModelTesterMixin, unittest.TestCase):
                 name = model.get_bias()
                 assert name is None
 
+    @tooslow
     def test_saved_model_creation(self):
-        # This test is too long (>30sec) and makes fail the CI
         pass
 
     def test_resize_token_embeddings(self):