Revert "Further simplification of save_global"

This reverts commit d9e02fb.

Author: ogrisel

cloudpickle/cloudpickle.py

@@ -631,7 +631,11 @@ def save_global(self, obj, name=None, pack=struct.pack):
                     return self.save_reduce(
                         _builtin_type, (_BUILTIN_TYPE_NAMES[obj],), obj=obj)
 
-            return self.save_dynamic_class(obj)
+            typ = type(obj)
+            if typ is not obj and isinstance(obj, (type, types.ClassType)):
+                return self.save_dynamic_class(obj)
+
+            raise
 
     dispatch[type] = save_global
     dispatch[types.ClassType] = save_global