t: fix severe &&-chain breakage

t: fix severe &&-chain breakage

These are tests which are missing a link in their &&-chain,
in a location which causes a significant portion of the test
to be missed (e.g., the test effectively does nothing, or
consists of a long string of actions and output comparisons,
and we throw away the exit code of at least one part of the
string).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>