Extend darklua end-to-end tests

[jeparlefrancais]

Darklua already uses some repositories that have unit tests to test commands and re-run unit tests to make sure the transformations did not change any expected behavior.

Additionally, darklua could include a set of tests that only run commands on Lua/Luau source code, and then run a linter like selene to make sure the code still makes sense. It is less precise than running a repository with unit tests, but it is still valuable as it would extend the amount of Lua code processed.

The wally index is a good place to discover new repos.