Remapped jar conflict when using multiple different mappings #1117
Description
Remapped jars are placed at .fabric/remappedJars/<gameId>-<gameVersion>-<loaderVersion>/<name>-<namespace>.jar (e.g. .fabric/remappedJars/minecraft-1.12.2-0.18.4/client-intermediary.jar). There is no mapping information other than the namespace baked into the path. This is not much of an issue in third-party launchers since they separate different installations entirely, but for the official launcher this is not the case. If you have e.g. a Legacy Fabric installation and an Ornithe installation for the same Minecraft version and Loader version, the one you install last will not work properly as it will run the jar from the first.
Code comments suggest this problem was known but I couldn't find it on the tracker. I apologize if it's a duplicate anyway.