Eng 6436 distinct reroute

This is the fast, simple but not the best efficient solution for DISTINCT with GROUP BY cases. We will create tickets to optimize it later.
Could we just comment this IF test and keep the else? In this way, there is harm to our existing code base and I am trying to use this information to push down some DISTINCT cases in my current work. 

I guess I will turn this check on in my new version.