mypy

19c5d5f7 - [mypyc] Improve failure reporting in default run test driver (#15563)

[mypyc] Improve failure reporting in default run test driver (#15563) Fix stdout flushing to avoid empty lines getting out of alignment with the rest of the output. Display the name of a failed test function, since it's sometimes not visible in the traceback (at least if something incorrectly propagates exceptions).