test: stabilize test-run-tests.t output We have reached a point where the duration in JSON reports of `test-run-tests.t` were greater or equal than 10 seconds, which doesn't match anymore the regex. For example here: https://ci.octobus.net/blue/organizations/jenkins/MercurialPy2/detail/MercurialPy2/276/pipeline ``` "diff": "", ? (re) - "end": "\s*[\d\.]{4,5}", ? (re) + "end": "10.040", "result": "skip", ? (re) ``` Instead of accepting more characters, I changed the regex to accept any number of digits before the `.` then 3 or 4 digits after. This way the regex is more precise (only one `.` is authorized and we can ensure that the precision doesn't change). Differential Revision: https://phab.mercurial-scm.org/D5966