Tests: move generate tests to the right mixin and delete redundant tests (#34464)

* tmp commit

* tmp commit

* cull overwrites of deleted tests

* typo

* more specific docstring

* make fixup

* parameterize at the top?

* correction

* more deletions :D

* tmp commit

* for VLMs too

* fix _check_outputs

* test nit

* make fixup

* fix another flaky

* test_generate_from_inputs_embeds -- handle missing attention mask

tests/models/nemotron/test_modeling_nemotron.py

@@ -92,8 +92,6 @@ class NemotronModelTest(GemmaModelTest):
     test_pruning = False
     fx_compatible = False
 
-    # used in `test_torch_compile`
-    _torch_compile_test_ckpt = "nvidia/nemotron-3-8b-base-4k-hf"
     # used in `test_torch_compile_for_training`
     _torch_compile_train_cls = NemotronForCausalLM if is_torch_available() else None