[tests] make cuda-only tests device-agnostic (#35607)

* intial commit

* remove unrelated files

* further remove

* Update test_trainer.py

* fix style

tests/models/diffllama/test_modeling_diffllama.py

@@ -676,7 +676,7 @@ class DiffLlamaModelTest(ModelTesterMixin, GenerationTesterMixin, PipelineTester
                 )
 
 
-@require_torch_gpu
+@require_torch_accelerator
 class DiffLlamaIntegrationTest(unittest.TestCase):
     # This variable is used to determine which CUDA device are we using for our runners (A10 or T4)
     # Depending on the hardware we get different logits / generations
@@ -689,7 +689,7 @@ class DiffLlamaIntegrationTest(unittest.TestCase):
             cls.cuda_compute_capability_major_version = torch.cuda.get_device_capability()[0]
 
     @slow
-    @require_torch_gpu
+    @require_torch_accelerator
     @require_read_token
     def test_compile_static_cache(self):
         # `torch==2.2` will throw an error on this test (as in other compilation tests), but torch==2.1.2 and torch>2.2