Update class_ir.py

Author: BobTheBuidler

mypyc/ir/class_ir.py

@@ -368,6 +368,7 @@ def serialize(self) -> JsonDict:
             "is_generated": self.is_generated,
             "is_augmented": self.is_augmented,
             "is_final_class": self.is_final_class,
+            "supports_weakref": self.supports_weakref,
             "inherits_python": self.inherits_python,
             "has_dict": self.has_dict,
             "allow_interpreted_subclasses": self.allow_interpreted_subclasses,