Make test-http(s)-set-timeout-server tests more similar and resolve the
following issues:
* `test-https-set-timeout-server.js` was missing some `assert`
statements, including with `http` module
* Both files were missing some calls to `common.mustCall()`
* Both files were calling `createServer()` in different ways
PR-URL: https://github.com/nodejs/node/pull/13822
Refs: https://github.com/nodejs/node/issues/13588
Refs: https://github.com/nodejs/node/pull/13625
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Alexey Orlenko <eaglexrlnk@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
