REL: ship `array-api-tests-xfails.txt` in wheels

[lucascolley]

For a library like MArray which wraps around array-api-strict and runs array-api-tests, there should be a way to easily apply the same skips/xfails that exist for array-api-strict in this repo. I think this would be easier if https://github.com/data-apis/array-api-strict/blob/main/array-api-tests-xfails.txt was shipped in the wheels. WDYT @ev-br ?

For mdhaber/marray#178.

[ev-br]

Sure if it helps downstream users, why not.

My experience in array-api-tests however, is that I needed the version from main anyway. The scenario is roughly this:

• a tweak in -tests uncovers an issue in -strict;
• the -strict fix lands in main, but the -strict release is ways off;
• to land the -tests fix need to have -tests CI green, and that needs either testing against -strict main, or waiting until a -strict release.

Whether this is relevant to any user other than -tests, I don't know, same for whether shipping the skips file helps users or gets in the way. If it helps them, sure, I don't see a problem including it.

[lucascolley]

at least so far, I believe MArray has just aimed for compatibility with the latest released version of array-api-strict. Having what we need in such a wheel would be nice.

Checking out the source would not be that bad given that we are already doing that for array-api-tests, but I don't think we should introduce extra complexity where it can be easily avoided.

[betatim]

I think shipping this makes sense. In terms of justification I'd apply the same as for shipping a package's tests: it makes it trivial to have the matching version of everything for the version you have installed. The cost is tiny for packages like array-api-strict

Yes you can mess around with git but that is several steps which means you have several chances to make a mistake, which then needs debugging.