Renaming a `.java` to `.kotlin` triggers an up-to-dateness bug

When a `.java` class gets renamed to `.kotlin`, it seems that a new plug gets created for the `.kotlin`, then it gets deleted by removing the `.java`, and then we get stuck in a bad state.

Workaround is to delete `build/foundPlugs`

Reproduce the rename from a `.java` class to `.kotlin` and inspect the resulting state under `build/foundPlugs`. The issue is done when the rename leaves the project up to date without creating and then deleting the new plug or requiring removal of `build/foundPlugs`.

Rédigé par le modèle d'indexation à partir du texte de l'issue.