DRILL-6952: Host compliant text reader on the row set framework
The result set loader allows controlling batch sizes. The new scan framework
built on top of that framework handles projection, implicit columns, null
columns and more. This commit converts the "new" ("compliant") text reader
to use the new framework. Options select the use of the V2 ("new") or V3
(row-set based) versions. Unit tests demonstrate V3 functionality.
closes #1683
