[llvm] [llvm][lit] Add option to run only the failed tests (PR #158043)

[Michael Buch via llvm-commits]

Michael137 wrote:

> Thanks, mostly looks good to me. I've got a couple more test suggestions:
> 
> 1. Show the behaviour when a test failed on the first run and was deleted before being run again with --filter-failed.
> 2. Show that a failed test that then subsequently passes (under a --filter-failed run) doesn't get run if the tests are executed with --filter-failed again. In other words, the "failed" state is cleared once a test has been rerun successfully.

Yup those seem like good things to test, thanks! Added in latest commit

https://github.com/llvm/llvm-project/pull/158043