Close all server testers
At least, all the ones I could find. Seems like the high memory usage was due to unclosed server testers calling a bunch of RPCs on each other. I believe the RPCs just continued to build up due a deadlock, and as a result they just allocated more and more memory.
This code currently deadlocks. You can reproduce the deadlock much faster with:
go test -v -tags='testing' -run=TestRenterPrices ./api