Follow-up "Check if the testdata repository is valid before running the evaluation, so it is checked just once"

[ruiAzevedo19]

          I think the language of a repository should come from the repository itself. I.e. either from the path it was created with (if it contains `golang` or `java`)... Or even better it is part of the specification file.

Could you add that as a follow-up refactoring? Not too important right now...

Originally posted by @bauersimon in https://github.com/symflower/eval-dev-quality/pull/265#discussion_r1677369351