INT-3455 Orderly Shutdown Improvements

JIRA: https://jira.spring.io/browse/INT-3455

Do not stop schedulers and executors - allows mid-flow
QueueChannels to be drained.

Stop all inbound MessageProducers (that are not OrderlyShutdownCapable).

INT-3455 Polishing; PR Comments

Change deprecate method usage to the new version
INT-3485: Remove final from `AE.stop(Runnable)`

JIRA: https://jira.spring.io/browse/INT-3485

Delegate to doStop() instead of overriding stop() directly

Delegated call to doStop() rather than stop(), added author tag and added unit test for custom doStop(runnable)

Polishing
INT-3479 Improve ServiceActivatingHandler.toString

JIRA: https://jira.spring.io/browse/INT-3479

- Remove null `beanName` in `AbstractStandardMessageHandlerFactoryBean`
- Change `ServiceActivatingHandler.toString()`
- Fix aggregator test timing
INT-3478 SftpPAOnceFileListFilter use getFilename

JIRA: https://jira.spring.io/browse/INT-3478

INT-3478: add test case

Polishing
Merge branch 'master' of github.com:spring-projects/spring-integration into INT-3460