This commit introduces support in AnnotatedElementUtils for finding
annotations declared on interfaces at the type level.
NB: this commit does not include support for finding annotations
declared on interface methods.
In order to maintain backward compatibility with @Transactional
annotation attribute processing, a new getAnnotationAttributes() method
has been added to AnnotatedElementUtils that provides a flag to control
whether interfaces should be searched.
SpringTransactionAnnotationParser and JtaTransactionAnnotationParser
have been updated accordingly to ensure that interfaces are not
unintentionally searched in the @Transactional resolution process.
This commit also introduces additional tests and updates TODOs for
SPR-12738.
Issue: SPR-12944, SPR-12738