test-82ba4ba1: Add support for a new behavior of chroot(1) + fix a typo.

    chroot with an argument of "/" no longer implicitly changes the
    current directory to "/", allowing changing only user credentials
    for a command.

    -- Coreutils-8.23 Changelog

Note that only the behavior of the tool has changed, not the behavior
of the syscall.

Reported-by: Rémi Duraffort <remi.duraffort@st.com>