INT-3578 Fix IllegalArgumentException

JIRA: https://jira.spring.io/browse/INT-3578

Adding `readDelay` to XML namespace for the `TcpConnectionFactoryFactoryBean`
caused an `IllegalArgumentException` when configuring with Java instea of
XML.
M-m-m. Don't know how it works for you, but this class is in the wrong place. Must be in the `test` directory, not `main`