The Scanner used by LayersTests treats a module-alias module as a reference to its target, but does not track the module-alias itself. The result is that when unreferenced modules are calculated, a module with an alias will never be treated as unreferenced.

The alias module should be tracked, and if it is unreferenced then its reference to its target can be removed, the same as with any other module.

These aliases should also be specifically tracked in the scan Result object so the WFCORE-6456 fix can take them into account.

LayersTest should also check for cases where alias modules are referenced by other modules and fail if those are found. Once a module is converted to an alias, existing references to it should be removed.