Ensure deterministic output

[bwitt]

Fix a few things that were preventing determinism:

• Sort filesystem-derived collections so that the output is deterministic
• fix a couple hashCode() calls to use String.hashCode() which is deterministic vs object.hashCode() which is not

Also add tests

Fixes #882

[bwitt]

@owenlejeune can you check if this fixes it for you? not sure I'm testing this right.

[owenlejeune]

i'd be happy to test a version with this integrated!

[bwitt]

@Alex009 what's a good way to do a dev build of this so we can test?

[nubesurrealista]

How can I test and help with this? I have interest on this because my case is the same as #882

[owenlejeune]

@Alex009 just wanted to check in on any updates to this

[ExNDY]

Hi,
Can you add prove tests for this changes? Or your metrics "was/now"? I'm try something like this in #881, but i dont remember was saved changes for PR or not. I think on current time that can be profits, but need more info for future.

[bwitt]

@ExNDY added tests, how does that look? does not seem to run the tests here in CI though