Do not remove half seq length in generation tests (#30016)

* remove seq length from generation tests

* style and quality

* [test_all] & PR suggestion

Co-authored-by: Joao Gante <joaofranciscocardosogante@gmail.com>

* Update tests/generation/test_utils.py

Co-authored-by: Arthur <48595927+ArthurZucker@users.noreply.github.com>

* [test all] remove unused variables

---------

Co-authored-by: Joao Gante <joaofranciscocardosogante@gmail.com>
Co-authored-by: Arthur <48595927+ArthurZucker@users.noreply.github.com>

tests/models/whisper/test_modeling_whisper.py

@@ -477,13 +477,11 @@ class WhisperModelTest(ModelTesterMixin, GenerationTesterMixin, PipelineTesterMi
         # cut to half length & take max batch_size=batch_size
         input_ids = input_ids[:batch_size, :, :]
 
-        # generate max 3 tokens
-        max_length = 4
         if config.eos_token_id is not None and config.pad_token_id is None:
             # hack to allow generate for models such as GPT2 as is done in `generate()`
             config.pad_token_id = config.eos_token_id
 
-        return config, input_ids, None, max_length
+        return config, input_ids, None
 
     def test_inputs_embeds(self):
         config, inputs_dict = self.model_tester.prepare_config_and_inputs_for_common()