JIRA: https://jira.spring.io/browse/INT-4197
Since `Collection<Message<?>>` can be possible only if we are dealing with messages as a group (`MethodInvokingMessageListProcessor`), the case with the `List<?>` param for Messaging Annotation method should not be treated as candidate for `messages` collection.
* Add `this.canProcessMessageList` condition to avoid `messages` SpEL expression when we are not in the `MethodInvokingMessageListProcessor` environment
**Cherry-pick to 4.3.x**
* Fix Array creating formatting
* Add comment about `ReflectiveMethodExecutor` to the `testRouterWithListParam()`
* Send one test data as as `Collection` to be sure that `@Router` parameters mapping works well
dd34f3de2a