AspectJExpressionPointcut leniently ignores non-composable interfaces

Issue: SPR-17003

(cherry picked from commit bccff73)

spring-core/src/main/java/org/springframework/util/ClassUtils.java

@@ -754,6 +754,8 @@ public abstract class ClassUtils {
 	 * @param interfaces the interfaces to merge
 	 * @param classLoader the ClassLoader to create the composite Class in
 	 * @return the merged interface as Class
+	 * @throws IllegalArgumentException if the specified interfaces expose
+	 * conflicting method signatures (or a similar constraint is violated)
 	 * @see java.lang.reflect.Proxy#getProxyClass
 	 */
 	@SuppressWarnings("deprecation")