tests: remove pid file by default Previously, killdaemons.py would kill PIDs listed in a file then leave the file lingering around. If the PIDs are killed, then there's no point leaving the PID file around. In the worst case, a later invocation of killdaemons.py (run-tests.py invokes killdaemons.py after running a test) could kill a separate process whose PID conflicted with a previously-killed process. By removing the PID file, we eliminate this possibility. Some tests were manually removing the PID file after calling killdaemons.py. So we update these tests to not do this. Differential Revision: https://phab.mercurial-scm.org/D3443