anchor.diff:      expect(result['unmodifiedFlags'].length, isPositive);
       bool found = false;
       for (var flag in result['unmodifiedFlags']) {
  -      if (flag['name'] == 'code_comments') {
  +      if (flag['name'] == 'trace_isolates') {
           found = true;
           expect(flag['flagType'], equals('bool'));
           expect(flag['valueAsString'], equals('false'));
  
positive.code: 
      // Modify a flag.
      var params = {
        'name' : 'code_comments',
        'value' : 'true',
      };
      result = await vm.invokeRpcNoUpgrade('setFlag', params);
  
negative.code:   (VM vm) async {
      // Modify a flag.
      var params = {
        'name' : 'trace_isolates',
        'value' : '123',
      };
      var result = await vm.invokeRpcNoUpgrade('setFlag', params);
  