test: simplify test-tls-client-default-ciphers

PR-URL: https://github.com/nodejs/node/pull/14928
Ref: https://github.com/nodejs/node/issues/12376


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>