Need help about pull request #3677

[soka...@yandex.ru]

Please read description of pull request https://github.com/django/django/pull/3677 and see changes (pull request is not big).

Then see tests.test_runner.tests.Sqlite3InMemoryTestDbs#test_transaction_support

The problem is that DiscoverRunner(verbosity=0).setup_databases() is broking something, so after this test my test can not pass.
The exception is like my changes about in-memory database sharing don't work in that moment.

When I running tests without Sqlite3InMemoryTestDbs, all works fine.

One more interesting thing - when I removed DiscoverRunner(verbosity=0).setup_databases(), test passes normally.
So why there are this line and what it is actually do?

Thanks!