Manual testing: SquashFS comments

Originally created by @CyrilBrulebois on #17565 (Redmine)

I hadn’t spotted this earlier (because I hadn’t dealt with RCs until now):

Note that for release candidates, we do not always optimize the ordering
of files in the SquashFS, which might make them boot somewhat slower.

which was last moved around in df54db34.

I’m not sure I’ve seen anything specific in the release process that would make updating SquashFS optional.

Maybe it was an accepted yet undocumented shortcut in a world where the DVD dance was a time sink, but it seems to me we should do the SquashFS dance unconditionally now, and remove those comments from the test.mdwn page.

What do you think?

Parent Task: #17376 (closed)