tests: remove last uses of GIT_TEST_GETTEXT_POISON=false

tests: remove last uses of GIT_TEST_GETTEXT_POISON=false

Follow-up my 73c01d25fe2 (tests: remove uses of
GIT_TEST_GETTEXT_POISON=false, 2021-01-20) by removing the last uses
of GIT_TEST_GETTEXT_POISON=*.

These assignments were part of branch that was in-flight at the time
of the gettext poison removal. See 466f94ec45e (Merge branch
'ab/detox-gettext-tests', 2021-02-10) and c7d6d419b0d (Merge branch
'ab/mktag', 2021-01-25) for the merging of the two branches.

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