Correct test for changes to native byte order - #11543

I've tested this locally with defining a non-native 'ndarray', and it fails apparently because the complex dtype([('f0', '>i4'), ('f1', 'S1')])'s byteorder is preserved under pickling and init_from_class. So the way out may rather be to specifically check for those (dtype.name = 'void*'), but I stand corrected if s390x passes.

Needs a rebase for the importlib_metadata issue (for Python 3.7)

closing in favour of the better solution at #11545