Add reproducibility testing

[aidanheerdegen]

As a team member I want automated reproducibility checks of code I add to the repository. This removes a burdensome task from me, but it also means the checking is consistent across the team, and any updates or improvements to the automated testing will benefit everyone. I can be confident that the checks are doing the right thing.

As a Model Release team member, an ACCESS-NRI team member and a model user I want automated reproducibility checks to ensure all code being merged does not change answers, and if it does then it must be documented.

As a Model Release team member I want these tests to only be run for trusted users, and only when the code change has passed compilation checks, and not automatically with every commit as it may consume too many resources. I will also require reproducibility testing to be peformed on the same HPC hardware on which the model runs.