misc/ios: inject the -u device_id option before any other arguments
The idevicedebugserverproxy command takes a port number without a
flag, like so:
idevicedebugserverproxy 3222
If the -u <device_id> flag is added afterwards, it is ignored and
the command use an arbitrary device. Instead, always inject the -u
flag before any other idevice command arguments.
While here, also kill any leftover idevicedebugserverproxy instance
previous (failed) runs might have left running.