`Module::getPackages` returns the set of package names for the packages in this module.

For unnamed modules, the specification and implementation have been corrected to return the names of the packages defined in the unnamed module. Prior to Java SE 16, `Module::getPackages` returned the set of package names for the packages defined in the module's class loader if the module was an unnamed module and the result included packages of other named modules defined in the module's class loader, if any.