Inline agg

This is part 1: Serial Inline aggregation contain table agg and group by agg with index.

Waiting for Jenkins.

That's the killer part of my dream. I was K.O by this problem.

Before what I changed on the seq/index scan executor for the projection temp tuple, they use the same address of the temp tuple on the same output table, which results in various wrong answers.

Now, if there is a projection inline node, I use a different temp tuple for it which make it safe here now. 

I guess it is safe for me to revert this change now.