Honor contract of @Repeatable in AnnotationUtils

Prior to this commit, the implementation of getRepeatableAnnotation()
in Spring's AnnotationUtils complied neither with the contract of
getAnnotationsByType() nor with the contract of
getDeclaredAnnotationsByType() as defined in AnnotatedElement in Java 8.

Specifically, unexpected results can be encountered when using Spring's
support for @Repeatable annotations: either annotations show up in the
returned set in the wrong order, or annotations are returned in the set
that should not even be found based on the semantics of @Repeatable.

This commit remedies this problem by deprecating the existing
getRepeatableAnnotation() methods and replacing them with new
getRepeatableAnnotations() and getDeclaredRepeatableAnnotations()
methods that comply with the contracts of Java's getAnnotationsByType()
and getDeclaredAnnotationsByType(), respectively.

Issue: SPR-13068

spring-context/src/main/java/org/springframework/scheduling/annotation/ScheduledAnnotationBeanPostProcessor.java

@@ -224,7 +224,7 @@ public class ScheduledAnnotationBeanPostProcessor implements BeanPostProcessor,
 				@Override
 				public void doWith(Method method) throws IllegalArgumentException, IllegalAccessException {
 					for (Scheduled scheduled :
-							AnnotationUtils.getRepeatableAnnotation(method, Schedules.class, Scheduled.class)) {
+							AnnotationUtils.getRepeatableAnnotations(method, Schedules.class, Scheduled.class)) {
 						processScheduled(scheduled, method, bean);
 						annotatedMethods.add(method);
 					}