Start migration annotation utility methods

Create internal variants of the existing `AnnotationUtils` and
`AnnotatedElementUtils` classes and migrate the existing classes to
use them.

The internal variants will be used to check that the same results are
given as we migrate the utils methods to use the new `MergedAnnotations`
API.

See spring-projectsgh-22562

spring-core/src/main/java/org/springframework/core/annotation/AbstractAliasAwareAnnotationAttributeExtractor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -64,7 +64,7 @@ abstract class AbstractAliasAwareAnnotationAttributeExtractor<S> implements Anno
 		this.annotationType = annotationType;
 		this.annotatedElement = annotatedElement;
 		this.source = source;
-		this.attributeAliasMap = AnnotationUtils.getAttributeAliasMap(annotationType);
+		this.attributeAliasMap = InternalAnnotationUtils.getAttributeAliasMap(annotationType);
 	}