Perform the full range of checks against all archived files instead of
looking only at the file type of a few of them. Also add a test of a
git archive with a prefix ending in with a slash, i.e. adding a full
directory level.
Signed-off-by: René Scharfe <rene.scharfe@lsrfire.ath.cx> Signed-off-by: Junio C Hamano <gitster@pobox.com>