anchor.diff:      if (_validators == null) {
         _validators = <DoctorValidator>[];
         _validators.add(new _FlutterValidator());
  +      _validators.add(new _HostExecutableValidator());
   
         if (_androidWorkflow.appliesToHostPlatform)
           _validators.add(_androidWorkflow);
  
positive.code: 
      return new ValidationResult(valid, messages,
        statusInfo: 'on ${osName()}, channel ${version.channel}');
    }
  }
  
  
negative.code: 
  import 'android/android_studio_validator.dart';
  import 'android/android_workflow.dart';
  import 'artifacts.dart';
  import 'base/common.dart';
  import 'base/context.dart';
  import 'base/file_system.dart';
  