Test pool recovery across independently evaluated module consumers

To test a suspected stale database reference in a bundled Node application, evaluate the database module twice in one shared global context, then trigger recovery in only one instance. Assert that an ordinary query through the other instance still works. A single-module readiness test can miss this defect, especially when Drizzle is mocked as an empty object and client shutdown has no effect. Use real Drizzle and postgres-js objects for the retired-client query while simulating only the timeout and replacement readiness result. This isolates reference ownership without accessing production; it does not prove that a particular deployed bundle actually has duplicate module instances.