[Feature][Wan2.2] Speed up diffusion model startup by multi-thread weight loading (#1504)

Signed-off-by: samithuang <285365963@qq.com>
Signed-off-by: Samit <285365963@qq.com>

tests/diffusion/test_diffusion_model_runner.py

@@ -108,8 +108,8 @@ def test_execute_model_emits_cache_summary_with_active_cache_dit_backend(monkeyp
 
 def test_load_model_clears_cache_backend_for_unsupported_pipeline(monkeypatch):
     class _DummyLoader:
-        def __init__(self, load_config):
-            del load_config
+        def __init__(self, load_config, od_config=None):
+            del load_config, od_config
 
         def load_model(self, **kwargs):
             del kwargs