Remove all traces of low_cpu_mem_usage (#38792)

* remove it from all py files

* remove it from the doc

* remove it from examples

* style

* remove traces of _fast_init

* Update test_peft_integration.py

* CIs

tests/models/dac/test_modeling_dac.py

@@ -280,18 +280,6 @@ class DacModelTest(ModelTesterMixin, PipelineTesterMixin, unittest.TestCase):
     def test_hidden_states_output(self):
         pass
 
-    @unittest.skip("No support for low_cpu_mem_usage=True.")
-    def test_save_load_low_cpu_mem_usage(self):
-        pass
-
-    @unittest.skip("No support for low_cpu_mem_usage=True.")
-    def test_save_load_low_cpu_mem_usage_checkpoints(self):
-        pass
-
-    @unittest.skip("No support for low_cpu_mem_usage=True.")
-    def test_save_load_low_cpu_mem_usage_no_safetensors(self):
-        pass
-
     def test_determinism(self):
         config, inputs_dict = self.model_tester.prepare_config_and_inputs_for_common()