tests: mark two failing tests under FAIL_PREREQS
Fix a couple of tests that would potentially fail under
GIT_TEST_FAIL_PREREQS=true.
I missed these when annotating other tests in
dfe1a17df9 ("tests: add
a special setup where prerequisites fail", 2019-05-13) because on my
system I can only reproduce this failure when I run the tests as
"root", since the tests happen to depend on whether we can fall back
on GECOS info or not. I.e. they'd usually fail to look up the ident
info anyway, but not always.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>