Add a test script for all archive attributes and their handling in
normal and bare repositories.  export-ignore and export-subst are
tested, as well as the effect of the option --worktree-attributes.
Signed-off-by: NRene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>