Revert signature of
ConfigurationClassPostProcessor#processConfigBeanDefinitions to its form
found in the 3.0.x line. Refactorings made during 3.1 development
caused otherwise package-private types such as
ConfigurationClassBeanDefinitionReader to escape through this public
method, causing issues for STS as well as being a general design issue.
Upon review, the refactorings could easily be backed out in favor of a
simpler approach, and this has been done.
This also means that ConfigurationClassBeanDefinitionReader can return
to package-private visibility, and this change has been made as well.
Issue: SPR-8200