test: use assert regexp in tls no cert test

Replace the `assert.throws` second argument from a Type to a `RegExp`
matching the entire error message.
Error message changes are `semver-major`, so we assert their content.

PR-URL: https://github.com/nodejs/node/pull/12891
Refs: https://github.com/nodejs/node/pull/12603


Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: David Cai <davidcai1993@yahoo.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>