crypto: fix faulty logic in iv size check

Fix a regression introduced in commit 2996b5c9 ("crypto: Allow GCM
ciphers to have a longer IV length") from April 2016 where a misplaced
parenthesis in a 'is ECB cipher?' check made it possible to use empty
IVs with non-ECB ciphers.

Also fix some exit bugs in test/parallel/test-crypto-authenticated.js
that were introduced in commit 4a408321 ("test: cleanup IIFE tests")
where removing the IFFEs made the test exit prematurely instead of just
skipping subtests.

PR-URL: https://github.com/nodejs/node/pull/9032
Refs: https://github.com/nodejs/node/pull/6376
Refs: https://github.com/nodejs/node/issues/9024


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Fedor Indutny <fedor@indutny.com>
Reviewed-By: Shigeki Ohtsu <ohtsu@ohtsu.org>