Fix #9903: Don't build houses around half-tile roads after a bridge or tunnel

src/town_cmd.cpp

@@ -1592,6 +1592,9 @@ static void GrowTownInTile(TileIndex *tile_ptr, RoadBits cur_rb, DiagDirection t
 			return;
 		}
 
+		/* Don't build houses around half-tile roads in the rare case we ended up on one. */
+		if (HasExactlyOneBit(cur_rb)) allow_house = false;
+
 		/* Possibly extend the road in a direction.
 		 * Randomize a direction and if it has a road, bail out. */
 		target_dir = RandomDiagDir();