tests: use $DAEMON_PIDS and killdaemons in largefiles test...
tests: use $DAEMON_PIDS and killdaemons in largefiles test
$DAEMON_PIDS is used by tests to make sure there will be no leftover
processes, the cycling through ports is needed because they are not
available for a new bind that quickly on some systems.
There are not enough $HGPORT variables available for each hg serve,
so use the killdaemons script before reusing ports.