runners: Fix tarball build for zfs-qemu-packages workflow (#17158)

The initial tarballs we built for for zfs-2.3.1 were incorrect since
they did not have a ./configure script, and their files were not
in a top level zfs-2.3.1/ directory. This commit copies the way we
built them on buildbot so the tarballs are created as expected.

Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Tino Reichardt <milky-zfs@mcmilk.de>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>