Revise method and parameter names in annotation support

In AnnotatedElementUtils, all methods pertaining to merging annotation
attributes have been renamed to "getMerged*()" and "findMerged*()"
accordingly. Existing methods such as getAnnotationAttributes(..) have
been deprecated in favor of the more descriptive "merged" variants.
This aligns the naming conventions in AnnotatedElementUtils with those
already present in AnnotationReadingVisitorUtils.

The use of "annotationType" as a variable name for the fully qualified
class name of an annotation type has been replaced with
"annotationName" in order to improve the readability and intent of the
code base.

In MetaAnnotationUtils.AnnotationDescriptor, getMergedAnnotation() has
been renamed to synthesizeAnnotation(), and the method is now
overridden in UntypedAnnotationDescriptor to always throw an
UnsupportedOperationException in order to avoid potential run-time
ClassCastExceptions.

Issue: SPR-11511

spring-context/src/main/java/org/springframework/context/event/ApplicationListenerMethodAdapter.java

@@ -248,7 +248,7 @@ public class ApplicationListenerMethodAdapter implements GenericApplicationListe
 	 */
 	protected String getCondition() {
 		if (this.condition == null) {
-			EventListener eventListener = AnnotatedElementUtils.findAnnotation(this.method, EventListener.class);
+			EventListener eventListener = AnnotatedElementUtils.findMergedAnnotation(this.method, EventListener.class);
 			if (eventListener != null) {
 				this.condition = eventListener.condition();
 			}