test: fix tests when npn feature is disabled.

ALPN test needs NPN feature to run. It also change the messages when
ALPN and NPN tests are skipped.

Fixes: https://github.com/nodejs/node/issues/11650
PR-URL: https://github.com/nodejs/node/pull/11655


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Fedor Indutny <fedor@indutny.com>