Inconsistent flat information when scanning from factorized table

[andyfengHKU]

In the planner, when scanning from a table, an output vector could either flat or unflat. However, this is not reflected on the processor side, a table scan operator always creates unflat datachunk and scans with size = 1. This should be the case for all scanning operators i.e. table scan, union all, aggregate scan, and hash join probe. A possible solution is to additionally tell which datachunk should be initialized as a flat datachunk during initialization.

This bug should be treated with higher priority then others.