Explore removing the Executable from JavaBeanExecutable

If we resolve , we might be able to get rid of Executable in JavaBeanExecutable. That would help with memory usage of the metadata, especially now that we resolve more of them (see JavaBeanParameter for instance).

Wondering if the overrides() calls won't be an issue. We should check if they are used post bootstrapping (e.g. when bootstrapping another subtype of a given type for instance).