t6423: fix test setup for a couple tests

t6423: fix test setup for a couple tests

Commit da1e295e00 ("t604[236]: do not run setup in separate tests",
2019-10-22) removed approximately half the tests (which were setup-only
tests) in t6043 by turning them into functions that the subsequent test
would call as their first step.  This ensured that any test from this
file could be run entirely independently of all the other tests in the
file.  Unfortunately, the call to the new setup function was missed in
two of the test_expect_failure cases.  Add them in.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>