Properly allow normal mods.toml mods to specify the module names and use a full module-info.

Make FMLModContainer read and apply Add-Opens and Add-Exports manifest entries from mod files.
Forge is now the `net.minecraftforge.forge` module instead of `forge`

https://forums.minecraftforge.net/topic/153333-proper-java-module-support-in-forge-mods/

src/main/java/net/minecraftforge/gametest/ForgeGameTestHooks.java

@@ -182,10 +182,10 @@ public class ForgeGameTestHooks {
         var batch = func.batchName();
         classes.add(batch);
 
-        int idx = batch.indexOf('.');
+        int idx = batch.lastIndexOf('.');
         while (idx != -1) {
             batch = batch.substring(0, idx);
-            idx = batch.indexOf('.');
+            idx = batch.lastIndexOf('.');
             classes.add(batch);
         }
     }