CPLQuadTree: add a more where the pfnGetBounds is not needed. And fix potential infinite recursion when inserting several points with identical coordinates in the mode with limited bucket size

git-svn-id: https://svn.osgeo.org/gdal/trunk@26820 f0d54148-0727-0410-94bb-9a71ac55c965
Merge branch 'trunk' into trunk_with_coverage