Anisotropic ORF tests broken on GitHub

[AaronDJohnson]

Problem:
test_orf** inside test_utils.py is currently being skipped on GitHub actions per PR #391.

Symptoms:
The test runs locally on my own Mac, but fails on GitHub runners with Error: Process completed with exit code 134. after hitting alm2map.

This error code (134) indicates either an out of memory error, or an index attempting to be accessed out of bounds. Given that this works on my own computer, but fails on GitHub, I'm guessing the former.

Goal:
Come up with a new test for the anisotropic ORF which doesn't fail on GitHub runners.

[vhaasteren]

If it's a memory issue, then we may be able to fix it by reducing nside in HealPIX. I have tested locally that nside=16 still passes the tests, and it fails for nside=8.

[vhaasteren]

So @AaronDJohnson, I did some recon here, even creating PR #404 . Going down to nside=4, the macos version succeeds for python 3.8, but it fails for the rest. I'm gonna guess this is a healpix/healpy problem.