Make extraPrivate opt-in instead of opt-out. Fixes #1708

test/transform/resource/after-ecj/BuilderDefaults.java

@@ -87,10 +87,4 @@ public final @Value @Builder class BuilderDefaults {
   public @java.lang.Override @java.lang.SuppressWarnings("all") java.lang.String toString() {
     return (((((("BuilderDefaults(x=" + this.getX()) + ", name=") + this.getName()) + ", z=") + this.getZ()) + ")");
   }
-  private @java.lang.SuppressWarnings("all") BuilderDefaults() {
-    super();
-    this.x = 0;
-    this.name = null;
-    this.z = 0L;
-  }
 }