rev-parse tests: don't ignore "git reflog" exit code

rev-parse tests: don't ignore "git reflog" exit code

Amend a test added in 9c46c054ae4 (rev-parse: tests git rev-parse
--verify master@{n}, for various n, 2010-08-24) so that we'll stop
ignoring the exit code of "git reflog" by having it on the
left-hand-side of a pipe.

Because of this I'd marked this test as passing under SANITIZE=leak in
f442c94638d (leak tests: mark some rev-parse tests as passing with
SANITIZE=leak, 2021-10-31). As all of it except this specific test
will now pass, let's skip it under the !SANITIZE_LEAK prerequisite.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>