Retain input ordering in `loadscope`

[Toad2186]

• Optionally retain input ordering in loadscope for tests where relative ordering matters. i.e. guarantee that, given [input_1, input_2], input_2 never runs before input_1. On any given worker, either input_1 has ran before input_2, or input_1 has never and will never run on this worker.

Thanks for submitting a PR, your contribution is really appreciated!

Here's a quick checklist that should be present in PRs:

• [x] Make sure to include reasonable tests for your change if necessary

• [x] We use towncrier for changelog management, so please add a news file into the changelog folder following these guidelines:

  • Name it $issue_id.$type for example 588.bugfix;
  • If you don't have an issue_id change it to the PR id after creating it
  • Ensure type is one of removal, feature, bugfix, vendor, doc or trivial
  • Make sure to use full sentences with correct case and punctuation, for example:

  Fix issue with non-ascii contents in doctest text files.

[zacharyburnett]

this would be very helpful for slow tests in small modules

[Toad2186]

If this ever get traction from upstream, I'll fix it ;).