Fix low memory beam search (#34746)

* fix

* higher max positions in tests

tests/generation/test_utils.py

@@ -1046,7 +1046,6 @@ class GenerationTesterMixin:
             self.assertListEqual(low_output.tolist(), high_output.tolist())
 
     @pytest.mark.generate
-    @unittest.skip("Started to break with https://github.com/huggingface/transformers/pull/33703")
     def test_beam_search_low_memory(self):
         # Check that choosing 'low_memory' does not change the model output
         for model_class in self.all_generative_model_classes:

tests/models/blip_2/test_modeling_blip_2.py

@@ -330,7 +330,7 @@ class Blip2TextModelDecoderOnlyTester:
         hidden_act="gelu",
         hidden_dropout_prob=0.1,
         attention_probs_dropout_prob=0.1,
-        max_position_embeddings=20,
+        max_position_embeddings=512,
         eos_token_id=2,
         pad_token_id=1,
         bos_token_id=0,