For both javax.lang.model.SourceVersion and java.lang.reflect.ClassFileFormatVersion, there is a need to represent the preview features when we query the version-specific methods.

While currently, there is no preview feature that cause such queries to differ from the latest version, when project valhalla delivers Value Classes (Preview) JEP, we anticipate to see a spike in such demands. As a result, we should prepare such an infrastructure before it arrives.