Function to export spatial types to not create correct output types

[noamross]

When converting spatial types to other formats via st_astext, st_aswkt, or st_asgeojson, the results are not of any TEXT or VARCHAR type, but instead are still spatial types. In working from R with the RMariaDB library, this results in the return type of the results being interpreted as empty blobs.

create table us_state_capitals (state varchar(50) primary key, city varchar(50), coord point);
insert into us_state_capitals values ('alabama', 'montgomery', st_srid(point(32.361667, -86.279167), 4326));
doltdb> describe us_state_capitals;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| state | varchar(50) | NO   | PRI |         |       |
| city  | varchar(50) | YES  |     |         |       |
| coord | point       | YES  |     |         |       |
+-------+-------------+------+-----+---------+-------+
doltdb> select st_astext(coord) as wkt from us_state_capitals;
+-----------------------------+
| wkt                         |
+-----------------------------+
| POINT(32.361667 -86.279167) |
+-----------------------------+
doltdb> CREATE TEMPORARY TABLE `temp` select st_astext(coord) as wkt from us_state_capitals limit 0;
doltdb> describe temp;
+-------+-------+------+-----+---------+-------+
| Field | Type  | Null | Key | Default | Extra |
+-------+-------+------+-----+---------+-------+
| wkt   | point | YES  |     |         |       |
+-------+-------+------+-----+---------+-------+

[jycor]

Fix for this issue should be in the release made earlier today.