RSRP-466615: Use Base Type does not replace types in 'is' operator

1. Call usebasetype on FirstUseBaseClass
   
2. select ClassToUse
   
3. check 'is' checkbox

  public class ClassToUse
  {
    private SecondUseBaseClass MethodWithUsages(object parameter)
    {
      var a = typeof(FirstUseBaseClass);
      if (parameter is FirstUseBaseClass)
        return null;
      var b = typeof(SecondUseBaseClass);
      if (parameter is SecondUseBaseClass)
        return null;

      return (SecondUseBaseClass) this;
    }
  }

  internal class SecondUseBaseClass : ClassToUse
  {
  }

  internal class FirstUseBaseClass : ClassToUse
  {
  }
}