set shape tests to be executable

git-svn-id: https://svn.osgeo.org/gdal/trunk@27450 f0d54148-0727-0410-94bb-9a71ac55c965
Initialize szFieldName to all nul chars and shorten it to 11 characters in SHPReadOGRFeatureDefn. (#5515)

git-svn-id: https://svn.osgeo.org/gdal/trunk@27451 f0d54148-0727-0410-94bb-9a71ac55c965