Test case
Move default logic to PlanGenerator
Use a values row with proper defaults in InsertGenerator.

Tweaks and minor cleanup to base and other derived.
Update expected
Consolidate OnlineHelper default handling as well
merge nathanlws: Fix handling of DEFAULT through REST

Merge pull request #1196 from nathanlws/sql-layer/fix-rest-column-defaults
https://github.com/FoundationDB/sql-layer/pull/1196