CI: avoid human error, automatically infer generative models (#33212)

* tmp commit

* move tests to the right class

* remove ALL all_generative_model_classes = ...

* skip tf roberta

* skip InstructBlipForConditionalGenerationDecoderOnlyTest

* videollava

* reduce diff

* reduce diff

* remove  on vlms

* fix a few more

* manual rebase bits

* more manual rebase

* remove all manual generative model class test entries

* fix up to ernie

* a few more removals

* handle remaining cases

* recurrent gemma

* it's better here

* make fixup

* tf idefics is broken

* tf bert + generate is broken

* don't touch tf :()

* don't touch tf :(

* make fixup

* better comments for test skips

* revert tf changes

* remove empty line removal

* one more

* missing one

tests/models/bigbird_pegasus/test_modeling_bigbird_pegasus.py

@@ -250,7 +250,6 @@ class BigBirdPegasusModelTest(ModelTesterMixin, GenerationTesterMixin, PipelineT
         if is_torch_available()
         else ()
     )
-    all_generative_model_classes = (BigBirdPegasusForConditionalGeneration,) if is_torch_available() else ()
     pipeline_model_mapping = (
         {
             "feature-extraction": BigBirdPegasusModel,
@@ -792,7 +791,6 @@ class BigBirdPegasusStandaloneDecoderModelTester:
 @require_torch
 class BigBirdPegasusStandaloneDecoderModelTest(ModelTesterMixin, GenerationTesterMixin, unittest.TestCase):
     all_model_classes = (BigBirdPegasusDecoder, BigBirdPegasusForCausalLM) if is_torch_available() else ()
-    all_generative_model_classes = (BigBirdPegasusForCausalLM,) if is_torch_available() else ()
     test_pruning = False
     is_encoder_decoder = False