As said in my first post, "You'll find this tool in file-storage"
In other words https://openacs.org/file-storage. It's named "query extractor: porter's version".
Ben's working on a fix for the util_memoize [list db_foo...] problem, BTW. He's got a quick hack for this particular case, and we've discussed the possibility of just walking the call stack looking for a [proc.queryname] match in the query dispatcher cache. He seems to think that will work, solving the problem in a more general way.
I haven't tested the query extractor on this construct, I'm sure it will fail. I'm not too worried, I've checked the entire 4.x release (all of it, not just the core) and there are only NINE examples of queries like this. We can pull these nine out by hand easily enough. If there were more I'd look into automating the process but it just ain't worth it for such a small number.
