(after fixing complicated b-tree bugs - I want to end my day with the
joy of fixing simple bugs)
This PR fix bug in emit (which was introduced after switch from
`HashMap` to `Vec`) and also align `CASE` codegen in case of `NULL`
result from `WHEN` clause with SQLite behaviour.
Reviewed-by: Jussi Saurio <jussi.saurio@gmail.com>
Closes#953
Move result row to `ProgramState` to mimic what SQLite does where `Vdbe`
struct has a `pResultRow` member. This makes it easier to deal with result
lifetime, but more importantly, eventually lazily parse values at the edges of
the API.
