Change MAP and ROW stack types

[dain]

Description

This PR changes MAP and ROW stack types to be SqlMap and SqlRow respectively. The new types do not extend block, and simply wrappers around the underlying column blocks. Both of these value classes have accessors for the underlying blocks and the offset into the blocks.

This PR contains a number of cleanup commit to simplify this conversion, and it also contains some minor fixes I found while making this change.

This is part of Project Hummingbird

Release notes

( ) Release notes are required, with the following suggested text:

# Section
* The Java stack type for a `MAP` value is now `SqlMap`, which does not implement `Block`. ({issue}`18948`)
* The Java stack type for a `ROW` value is now `SqlRow`, which does not implement `Block`. ({issue}`18948`)