Raise statistic target during estimation test

Possibly fixes #2851 (probability is statitics based)

git-svn-id: http://svn.osgeo.org/postgis/trunk@12815 b70326c6-7e19-0410-871a-916f4a2858ee
Drop dependency of estimation test on XML type (#2151)

git-svn-id: http://svn.osgeo.org/postgis/trunk@12816 b70326c6-7e19-0410-871a-916f4a2858ee