Some US roads were not included in tiles, because the `ST_AsMVTGeom` did not transform geometry (result was NULL). This PR is trying to fix the geometry for `ST_AsMVTGeom`, even if the geometry is marked as valid (`ST_IsValid`). The odd geometry was caused by simplification when it could create `LINESTRING(1 1, 2 2, 1 1)` linestring, which in some cases was not converted into MVT.
Also, for the US (on zoom 4) keeps just the network `us-interstate` and the `highway=motorway` or `osm_national_network(network)` for the rest of the world.
e6faa69a70