Remapping deletes duplicate classes from jars

[Juuxel]

See example project: https://github.com/Juuxel/duplicate-mods

• There are two mod dependencies, a.jar and b.jar
  • a.jar has classes A, B
  • b.jar has classes A, B, C, D
• When you build the project with gradlew classes, Loom will remap the mods
• If you take a look in .gradle/loom-cache/remapped_mods, only one of the jars will have the classes A, B even though both inputs have them

This is a simplified test case from a real-life mod setup where a crossplatform mod shadows some of its modules but still depends on the other modules in its POM.

[modmuss50]

Fixing this requires a change on tiny remappers side of things. I will move this issue to that repo.

At the very least I think it should bail out in this case?