One thing to suggest: Instead of picking what tests to run, it may be better to change the order in which tests are run instead. In particular: sorting tests

One thing to suggest: Instead of picking what tests to run, it may be better to change the order in which tests are run instead. In particular: sorting tests by "how often did this test change results when these lines were modified?", descending. (And also running a background job that asserts that tests don't change results when run in a different order.)