Test failures on nightly ARM64 wheel builds.

See https://app.travis-ci.com/github/MacPython/numpy-wheels/jobs/549013361.
```
FAILED core/tests/test_mem_policy.py::test_new_policy - AssertionError: asser...
FAILED core/tests/test_umath.py::TestComplexFunctions::test_loss_of_precision[complex256]
```