Use canonical names in error messages in annotation processing

[sbrannen]

Currently, we invoke Class.getName() when building error messages during annotation processing, resulting in exceptions like the following (bold emphasis added).

Attribute 'chars' in annotation org.springframework.core.annotation.AnnotationUtilsTests$CharsContainer should be compatible with [C but a [I value was returned

By switching to canonical names, we can improve such errors messages as follows.

Attribute 'chars' in annotation org.springframework.core.annotation.AnnotationUtilsTests.CharsContainer should be compatible with char[] but a int[] value was returned