[Enhancement] Create a dedicated test suite for scripts

[FrancescoMolinaro]

On the Angular project we currently use many scripts for various reasons: translation synchronization, build, etc.
It would be nice to have at least some basic tests to prevent issues during code updates, as has already happened — for instance with the translation script (ref #4842). In this way we could better maintain the expected behaviors also for larger scripts; as an example we can take a PR like #4528, which introduces a new script for generating decorators.

[lgeggleston]

Thanks for the idea @FrancescoMolinaro! Putting this on the 11.0 board for volunteers; this also seems like something that could be contributed in small pieces, if any volunteers want to add tests for one of the frontend scripts at a time.