Check for dynamic module

Add a condition while looking up modules to see if the module is
registered as dynamic, returning None if so. This means resources
belonging to modules registered as dynamic will be treated as if they
had no module, or belonged to __main__.

cloudpickle/cloudpickle.py

@@ -234,6 +234,9 @@ def _lookup_module_and_qualname(obj, name=None):
     if module_name == "__main__":
         return None
 
+    if _is_dynamic_module(module_name):
+        return None
+
     # Note: if module_name is in sys.modules, the corresponding module is
     # assumed importable at unpickling time. See #357
     module = sys.modules.get(module_name, None)