Major Description
Some decorators used to test authorization don't close and null out references to Connection objects when they have completed. Since these tests often create/boot single-use databases, and the Connection objects have references to the database instance and, directly or indirectly, many of its modules, this prevents much garbage from being removed from the heap after the tests have completed and shut down their single-use databases. We should close the default connection and clear the reference to it when tearing down these decorators, so the space is released for subsequent tests to use.
This problem affects decorators returned by the following methods:
DatabasePropertyTestSetup.builtinAuthenticationNoTeardown()
TestConfiguration.sqlAuthorizationDecorator()
TestConfiguration.sqlAuthorizationDecoratorSingleUse()
These methods return modified versions of DatabasePropertyTestSetup where the tearDown() method is a no-op.