t5548: add new porcelain test cases
Add two more test cases exercising git-push(1) with `--procelain`, one
exercising a non-atomic and one exercising an atomic push.
Based-on-patch-by: Jiang Xin <zhiyou.jx@alibaba-inc.com>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
authored by