Fix cursor_to_xml in tableforest false mode
It only produced <row> elements but no wrapping <table> element.
By contrast, cursor_to_xmlschema produced a schema that is now correct
but did not previously match the XML data produced by cursor_to_xml.
In passing, also fix a minor misunderstanding about moving cursors in
the tests related to this.
Reported-by: filip@jirsak.org
Based-on-patch-by: Thomas Munro <thomas.munro@enterprisedb.com>