Move back into AVA proper

[novemberborn]

avajs/ava#925 mentions the code was extracted to "allow other tools (i.e. atom-ava, linter, etc) to have access to the file selection logic."

I don't see it in atom-ava's dependencies though.

Given the tight coupling I think it's easier if we can maintain this in AVA itself. We'll have to use TAP again for tests, so that sucks, but thinking about compatibility with current AVA releases sucks more IMHO.

@avajs/core?

[sotojuan]

I think if no one has really found a use for it outside of AVA it's safe to put it back, but we should make sure no projects actually use it (or at least no "blessed" AVA-related projects use it).

[sindresorhus]

I agree. In hindsight, I think we should have only done it out of actual need, not imaginary future need.

Doesn't look like anyone is using it anyways: https://www.npmjs.com/browse/depended/ava-files

[novemberborn]

Cool, I'll raise a ticket with AVA itself.

[sindresorhus]

Fixed by avajs/ava#1196