Autointersections of an object were treated as nodes, so the wrong result.

per-file comments:
  mysql-test/r/gis.result
Bug #1043845 st_distance() results are incorrect depending on variable order.
        test result updated.
  mysql-test/t/gis.test
Bug #1043845 st_distance() results are incorrect depending on variable order.
        test case added.
  sql/item.cc
        small fix to make compilers happy.
  sql/item_geofunc.cc
Bug #1043845 st_distance() results are incorrect depending on variable order.
        Skip intersection points when calculate distance.