We don't need to check for duplicate test numbers, we don't have them,
and either way test-lint-duplicates doesn't work in this situation.
Also, while we are on it, enable test-lint-shell-syntax to check for sh
errors.
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>