python3.8: suppress warnings

[thautwarm]

purescript-prelude.py/python-ffi/Data/Ord.py

Line 22 in 1bf0398

if o is not 0:

We use is to compare literals, and we know the code is running on CPython and this is important internal optimizations. Python3.8 roughly emits warnings for any use like this, and we should suppress them.