PreparedLineStringDistance.isWithinDistance fails for containing polygons

[dr-jts]

As a follow-on to #958, PreparedLineStringDistance.isWithinDistance (and hence GEOSPreparedDistanceWithin) does not work for LineStrings when the test geometry is a Polygon which contains the indexed line(s). This is because the PreparedLineStringDistance.isWithinDistance does not check if the test geometry contains any points of the indexed geometry.

Here's a test case:

template<>
template<>
void object::test<13>
()
{
    checkDistanceWithin(
        "LINESTRING (30 30, 70 70)",
        "POLYGON ((0 100, 100 100, 100 0, 0 0, 0 100))",
        1,
        1
    );
}