This issue originates from a need in Spring Data JPA, wherein a custom
InstantiationAwareBeanPostProcessor may alter the predicted type of
FactoryBean objects, effectively preventing retrieval of those beans via
calls to #getBeansOfType(FactoryBean.class).
The reason for this "masking effect" is that prior to this change, the
implementation of AbstractBeanFactory#isFactoryBean considered only the
"predicted type" returned from #predictBeanType when evaluating
assignability to FactoryBean.class
The implementation of #isFactoryBean now ensures that not only the
predicted bean type is considered, but also the original bean
definition's beanClass (if one is available).
Issue: SPR-8954