Revert "Fix self-connection not showing as low stress"

This reverts commit 706ef97.

Revert self-connection fix due to extreme slowness in DB operations

pybna/sql/connectivity/tile_based_connectivity.sql

@@ -107,28 +107,12 @@ WHERE
         tmp_allverts.start_vid = source_vert.{vert_id_col}
         AND tmp_allverts.end_vid = target_vert.{vert_id_col}
     )
-    AND source.id != target.id
 ORDER BY
     source_id,
     target_id,
     agg_cost ASC;
 
 DROP TABLE pg_temp.tmp_allverts;
-
-INSERT INTO tmp_lostress
-SELECT
-    source.id AS source_id,
-    target.id AS target_id,
-    0
-FROM
-    tmp_allblocks source,
-    tmp_allblocks target,
-    {tiles_table} tile
-WHERE
-    tile.{tile_id_col}={tile_id}
-    AND ST_Intersects(source.geom,tile.{tile_geom_col})
-    AND source.id = target.id;
-
 CREATE INDEX tidx_lostress ON tmp_lostress (source_id,target_id);
 ANALYZE tmp_lostress;