Polish instance check

- Remove possible call to expensive
  BeanFactory#toString.
- Backport #569
- Relates #573

spring-statemachine-core/src/main/java/org/springframework/statemachine/config/common/annotation/AbstractImportingAnnotationConfiguration.java

@@ -128,8 +128,7 @@ public abstract class AbstractImportingAnnotationConfiguration<B extends Annotat
 
 	@Override
 	public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
-		Assert.isInstanceOf(ListableBeanFactory.class, beanFactory,
-				"beanFactory be of type ListableBeanFactory but was " + beanFactory);
+		Assert.isInstanceOf(ListableBeanFactory.class, beanFactory);
 		this.beanFactory = beanFactory;
 	}
 

spring-statemachine-core/src/main/java/org/springframework/statemachine/processor/StateMachineHandlerCallHelper.java

@@ -109,8 +109,7 @@ public class StateMachineHandlerCallHelper<S, E> implements InitializingBean, Be
 			// in a same way further things will be skipped in afterPropertiesSet()
 			return;
 		}
-		Assert.state(beanFactory instanceof ListableBeanFactory,
-				"Bean factory must be instance of ListableBeanFactory, was " + beanFactory);
+		Assert.isInstanceOf(ListableBeanFactory.class, beanFactory);
 		this.beanFactory = (ListableBeanFactory)beanFactory;
 	}