Earlier, fba4f1 (grep -P: Fix matching ^ and $) fixed an ancient bug. Add
some tests to protect the change from future breakages; a slightly broken
version of this was a part of the originally submitted patch.
Signed-off-by: Michał Kiedrowicz <michal.kiedrowicz@gmail.com> Signed-off-by: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl> Signed-off-by: Junio C Hamano <gitster@pobox.com>