JIRA: https://jira.spring.io/browse/INT-3565
Cast to `IntegrationObjectSupport` fails if the handler is
already proxied in `AbstractSimpleMessageHandlerFactoryBean`.
Conflicts:
spring-integration-core/src/main/java/org/springframework/integration/config/AbstractSimpleMessageHandlerFactoryBean.java
Resolved.
INT-3565 Polishing
- Fix test.
- enhance test to show that directly bound message handler beans are not advised if already proxied.
f73e920696