tests: de-flake test-run-tests.t's "--jobs=2 --first" test Once in a while, test-nothing.t finished before test-failure.t or test-failure-copy.t (I haven't checked which one actually gets run first). Since there already are two tests that will fail in the same way, just run those two instead so the diff will be reproducible and not timing-dependent. The test case was added in 9a20f53e436f (run-tests: handle --jobs and --first gracefully, 2014-10-09), and I have checked that backing that out results in two failures being printed. Note that the summary may still include multiple tests even if --first is given, it's just that the diff is only printed for the first failure. Differential Revision: https://phab.mercurial-scm.org/D1186