Codecs are inconsistents: utf-32 has working getstate() / setstate() methods, whereas utf-8-sig and utf-16 don't (getstate() always return 0, setstate() does nothing).

> Simply moving py3ks getstate/setstate implementation 
> over to 2.x might do the trick.

That's what my patch does :-) It just a copy/paste of Python3 code. It does fix #5006 tests (which are re-enabled by the patch). Using the patch, it's possible to save/restore utf-8-sig and utf-16 codecs state.