tests: clarify that duplicate flag processors is not an error The flag processors test for duplicate processors for a single flag was misleading because the file from the previous test case caused it to fail (making the "echo 'this should fail' > file" part irrelevant). Let's remove the leftover from the previous test case to make it clear that duplicate flag processors results only in a warning. Note that duplicate flag processors would have resulted in a failure (not just a warning) until ea1c2eb7abd3 (extensions: catch uisetup and extsetup failures and don't let them break hg, 2017-06-06). I remember expressing my concern about ending up with half-loaded extensions. It would be pretty unfortunate to have double-encoded revlog content enter a repo, so maybe we should reconsider? Differential Revision: https://phab.mercurial-scm.org/D201