Remove code that preserved _original_py_fns on C++ classes.

This no longer appears to be used.

PiperOrigin-RevId: 737715578

Author: hawkinsp

jax/_src/util.py

@@ -668,17 +668,12 @@ def wrapper(cls):
 
     exclude_methods = {'__module__', '__dict__', '__doc__'}
 
-    originals = {}
     for attr_name, attr in cls.__dict__.items():
       if attr_name not in exclude_methods:
-        if hasattr(_original_func(attr), "_use_cpp"):
-          originals[attr_name] = attr
-        else:
+        if not hasattr(_original_func(attr), "_use_cpp"):
           setattr(cpp_cls, attr_name, attr)
 
     cpp_cls.__doc__ = cls.__doc__
-    # TODO(pschuh): Remove once fastpath is gone.
-    cpp_cls._original_py_fns = originals
     return cpp_cls
 
   return wrapper