Include a non-database test context
Description
Building #18337 (closed), I've got a set of specs that don't need database persistence. I'm adding 7 examples and this still adds considerable time to the total test run (several seconds) because a database is being set up around each spec and torn down again. But I'm not doing any database work.
Proposal
Include a database-free context that specs can opt in to, in the same way that JS-requiring specs opt into that expensive context. Ensure that newly added specs are reviewed with an eye to making them database-free if possible.