update gnu ref to 9.9 + improve the script

[sylvestre]

No description provided.

[cakebaker]

You also have to adapt the paths to numfmt.pl as the file has been moved from tests/misc to tests/numfmt. It causes the following error in the GNU tests jobs:

sed: can't read tests/misc/numfmt.pl: No such file or directory

[github-actions]

GNU testsuite comparison:

GNU test failed: tests/cksum/cksum-c. tests/cksum/cksum-c is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/misc/unexpand. tests/misc/unexpand is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/sort/sort-compress. tests/sort/sort-compress is passing on 'main'. Maybe you have to rebase?
Congrats! The gnu test tests/du/bigtime is now passing!

[sylvestre]

i updated #9127