t0000: drop "known breakage" test

t0000: drop "known breakage" test

Having a simulated "known breakage" test means that the test
suite will always tell us there is a bug to be fixed, even
though it is only simulated.

The right way to test this is in a sub-test, that can also
check that we provide the correct exit status and output.
Fortunately, we already have such a test (added much later
by 5ebf89e).

We could arguably get rid of the simulated success test
immediately above, as well, as it is also redundant with the
tests added in 5ebf89e. However, it does not have the
annoying behavior of the "known breakage" test. It may also
be easier to debug if the test suite is truly broken, since
it is not a test-within-a-test, as the later tests are.

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