[tests.router] Add delay between store and lookup
[tests.router] Add delay between store and lookup

TheThingsNetwork/ttn,TheThingsNetwork/ttn,TheThingsNetwork/ttn,mgranberry/ttn,jvanmalder/ttn,jvanmalder/ttn,LoRaWanSoFa/ttn,mgranberry/ttn,jvanmalder/ttn,LoRaWanSoFa/ttn,mgranberry/ttn