nimbus-fml: Make the output deterministic.

[PieroV]

Changed some HashMaps with BTreeMaps to ensure the order of the output is deterministic.

Pull Request checklist

• Breaking changes: This PR follows our breaking change policy
  • This PR follows the breaking change policy:
    • This PR has no breaking API changes, or
    • There are corresponding PRs for our consumer applications that resolve the breaking changes and have been approved
• Quality: This PR builds and tests run cleanly
  • Note:
    • For changes that need extra cross-platform testing, consider adding [ci full] to the PR title.
    • If this pull request includes a breaking change, consider cutting a new release after merging.
• Tests: This PR includes thorough tests or an explanation of why it does not
  • It doesn't add new features, it changes a data type used here and there
  • Maybe it could be worth to include a test to check the output always follows a certain order, in case could you help me for that? 🙂
• Changelog: This PR includes a changelog entry in CHANGELOG.md or an explanation of why it does not need one
  • Any breaking changes to Swift or Kotlin binding APIs are noted explicitly
• Dependencies: This PR follows our dependency management guidelines
  • Any new dependencies are accompanied by a summary of the due diligence applied in selecting them.

Branch builds: add [firefox-android: branch-name] to the PR title.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 4 lines in your changes missing coverage. Please review.

Project coverage is 22.66%. Comparing base (8fd08c6) to head (db52b2b).

Files	Patch %	Lines
...port/nimbus-fml/src/intermediate_representation.rs	0.00%	2 Missing ⚠️
components/support/nimbus-fml/src/parser.rs	0.00%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6283   +/-   ##
=======================================
  Coverage   22.66%   22.66%           
=======================================
  Files         332      332           
  Lines       29804    29804           
=======================================
  Hits         6754     6754           
  Misses      23050    23050           

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[linabutler]

Thanks so much for doing this, @PieroV!

This looks great to me—though it looks like the test fixtures might need updating, from those Clippy and test failures 👀—but let's have Charlie and Beth give the official review.

[jeddai]

Ye, Lina is right, there's a few things you'll need to adjust but otherwise this looks great!

For clippy, run this from the base repo directory and it'll show you its issues: ./automation/tests.py rust-clippy

cargo test in the /components/support/nimbus-fml folder should show you the test failures.

All-in-all I think there shouldn't be too much to change to get this in a spot where it's good to merge!

The pull request has been modified, dismissing previous reviews.

[PieroV]

I tried to run cargo teston the rebased branch, but I can't find test failures, at most some tests are ignored.

Should I pass additional arguments?

[jeddai]

Looks great!! Thank you for your contribution ❤️