What will happen to the tailed beast if the jinchuruki is killed?
After a period of time the tailed beast will revive, so they will survive the death of the host.


  However, it is revealed that the tailed beasts can actually survive their jinchūriki's deaths, with the only consequence being that it will take time for them to revive without a host.


Source: Narutopedia - in the second paragraph of that section.