url: change null password handling

Pulls in new URL parsing tests from w3c web-platform-tests and updates
null password handling.

Refs: https://github.com/w3c/web-platform-tests/commit/e0012406859014e8f31dbaf12122d0cd10249db4
Refs: https://github.com/whatwg/url/pull/186
PR-URL: https://github.com/nodejs/node/pull/10601
Fixes: https://github.com/nodejs/node/issues/10595


Reviewed-By: Michal Zasso <targos@protonmail.com>
Reviewed-By: Italo A. Casas <me@italoacasas.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>