Improve writing of SHPP_TRIANGLES

git-svn-id: https://svn.osgeo.org/gdal/trunk/gdal@26878 f0d54148-0727-0410-94bb-9a71ac55c965
OpenFileGDB: SHPT_MULTIPATCH has Z components

git-svn-id: https://svn.osgeo.org/gdal/trunk/gdal@26879 f0d54148-0727-0410-94bb-9a71ac55c965