GTiff: fix reading a single-strip TIFF file where the single strip is bigger than 2GB, issues found on 32bit builds only (#5403)

git-svn-id: https://svn.osgeo.org/gdal/trunk@26998 f0d54148-0727-0410-94bb-9a71ac55c965
Merge branch 'trunk' into trunk_with_coverage