I'd say, put it in a vm. Then you can make it read only and restart whenever.
Or when coding stuff yourself sqlite allows you to store things in ram (it will disappear as soon as the connection is closed) and it could build that table from an existing table. (you'll need to filter out some sqlite
commands which would allow merging with other files or overwrite certain limits you've put in place and maybe other stuff to keep it secure though). Or you could randomly delete the files and build a new table if it doesn't exist.(still filter some of the input as above).
Getting the usual databases to store things in ram isn't super tricky, but getting them to work when you reset it might be harder. And certain commands could still result in their output being stored in a location of their choosing.
The VM option would be the nicest though since it will be 100% realistic, but having several VMs up on a limited set of IPs or resetting things at an appropriate time might be tricky(trust me, its been on the HTS wishlist for far too long)
But with only 1 instance alive for each different type of vuln it could be done with a simple cron job restarting it every x minutes.
Other folks might have more ideas.
I'd love to hear how this works out, keep us updated ^^