Feed in the original ClassReader to ensure the constant pool is not excessively mangled.

src/main/java/net/md_5/specialsource/JarRemapper.java

@@ -173,7 +173,7 @@ public class JarRemapper extends Remapper {
             }
         }
 
-        ClassWriter wr = new ClassWriter(0);
+        ClassWriter wr = new ClassWriter(reader, 0);
         RemappingClassAdapter mapper = new RemappingClassAdapter(wr, this);
         reader.accept(mapper, ClassReader.EXPAND_FRAMES); // TODO: EXPAND_FRAMES necessary?
 

src/main/java/net/md_5/specialsource/RemapperPreprocessor.java

@@ -143,7 +143,7 @@ public class RemapperPreprocessor {
                 }
             }
 
-            ClassWriter cw = new ClassWriter(0);
+            ClassWriter cw = new ClassWriter(classReader, 0);
             classNode.accept(cw);
             bytecode = cw.toByteArray();
         }