Remove test-jar artifacts from Maven projects and relocate classes. The
majority of utilities now live in the `spring-boot-testsupport` module.
This update will help us to deploy artifacts using the standard Maven
deploy plugin in the future (which doesn't support the filtering of
individual artifacts).
Fixes gh-9493
Add an annotation processor that generates properties files for certain
auto-configuration class annotations. Currently attribute values from
@AutoConfigureOrder, @AutoConfigureBefore, @AutoConfigureAfter and
@ConditionalOnClass annotations are stored.
The properties file will allow optimizations to be added in the
`spring-boot-autoconfigure` project. Primarily by removing the need
to ASM parse as many `.class` files.
See gh-7573
