anchor.diff:            session.top,
             m1,
             m2,
  -          session.rerun);
  +          session.rerun,
  +          session.dartSdkRevision);
         divergences = fuzz.run();
       } catch (e) {
         print('Isolate: $e');
  
positive.code:   final String mode1;
    final String mode2;
    final bool rerun;
  
    // Test.
    Random rand;
  
negative.code: 
    void showReproduce() {
      print("\n-- BEGIN REPRODUCE  --\n");
      print("DART SDK REVISION: $dartSdkRevision\n");
      print("dartfuzz.dart --${fp ? "" : "no-"}fp --${ffi ? "" : "no-"}ffi "
          "--${flatTp ? "" : "no-"}flat "
          "--seed ${seed} $fileName");
  