[test] computing ECC cofactors: regression test

[test] computing ECC cofactors: regression test

This is a forward port from
    https://github.com/openssl/openssl/pull/9781
for the test logic introduced by
    https://github.com/openssl/openssl/pull/9727

As @mattcaswell commented
(https://github.com/openssl/openssl/pull/9781#discussion_r321621541):

> These `TEST_true` calls should be `!TEST_false` because we are
> *expecting* a failure.
> The difference is that the test framework will print error details if
> the test doesn't give the expected answer.
> So by using `TEST_true` instead of `!TEST_false` we'll get error
> details printed, but the test will succeed anyway.

(cherry picked from commit e8aafc891d9bd7fa1cce0401d858ef842f09b49e)

Reviewed-by: Nicola Tuveri <nic.tuv@gmail.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9797)