anchor.diff:      print('\nrunning $cmd yields:\n'
           '${res.exitCode}\n${res.stdout}\n${res.stderr}\n');
     }
  -  if (res.exitCode == -sigkill) {
  -    return new TestResult(ResultCode.timeout, res.stdout);
  -  } else if (res.exitCode != 0) {
  -    return new TestResult(
  -        ResultCode.error, '${res.exitCode}\n${res.stdout}\n${res.stderr}\n');
  -  }
  -  return new TestResult(ResultCode.success, res.stdout);
  +  return TestResult(res.stdout, res.stderr, res.exitCode);
   }
   
   /// Abstraction for running one test in a particular mode.
  
positive.code:       }
      } else {
        // For any other divergence, always report what went wrong.
        if (result1.code != ResultCode.success) {
          print('\nfail1:\n${result1.output}\n');
        }
        if (result2.code != ResultCode.success) {
          print('\nfail2:\n${result2.output}\n');
        }
      }
    }
  
negative.code:             return ReportStatus.reported;
            }
            break;
          case -sigkill:
            // Both had a time out.
            numTimeOut++;
            break;
          default:
            // Both had an error.
            numNotRun++;
            break;
  