JPEG: in compressor, increase default val of max_memory_to_use to 500MB

git-svn-id: https://svn.osgeo.org/gdal/trunk@28210 f0d54148-0727-0410-94bb-9a71ac55c965
In tiff_write_126, increase JPEGMEM to make Windows Travis-CI instances happy

git-svn-id: https://svn.osgeo.org/gdal/trunk@28211 f0d54148-0727-0410-94bb-9a71ac55c965
Merge branch 'trunk' into trunk_with_coverage