test_binary_compatibility & test_prefault segfault on ppc64 & s390x

[jayvdb]

c.f. https://build.opensuse.org/package/show/devel:languages:python/python-annoy

index_test.py::IndexTest::test_binary_compatibility & test_prefault failure is occurring only on ppc64 & s390x, tested both on Python 3.6 and 3.8

[erikbern]

interesting. maybe it's something with how they represent binary numbers in different ways