run-tests: allow some slack about 'waiting on lock' message It is common to run the tests on very loaded machine when concurrent run might take a bit longer. Such message are usually harmless, but anoying as they break the tests. Test that explicitly depends on this value have been adjusted. This make them more robust anyway. A fun case was `test-clone-pull-corruption.t` which, without the previous changeset introducing extra flushing, ended use having a line 31 (`pulling from ../source`) changing order because the warning message was no longer flushing stdin before using stderr (stderr being invisible in the test). Differential Revision: https://phab.mercurial-scm.org/D9507

pull: flush stdin after the `pull from` message That message can end up being flushed after some stderr message in some case, leading to confusing output. Differential Revision: https://phab.mercurial-scm.org/D9506

tests: explicitly skip the lock warning in some remotefilelog tests The output was conditional zed, so lets official skip it instead. Differential Revision: https://phab.mercurial-scm.org/D9505

tests: use the right python when running dummyssh for narrow some plateform no longer have a `python` executable. Differential Revision: https://phab.mercurial-scm.org/D9504