This avoids fetching data that will not be requested when the "cursor" is only moved and no data requested. That is typically what RowSetCache does when its own cursor is moved within its window.

This basically makes the whole {next,previous,absolute,...}_checked story obsolete, by basically always being as fast as the i_bFetchRow==false case, but in a safer way.

Change-Id: I89eaf277069736b3077bde8b45325929db290f2d