url: do not decode arbitrary %2e sequences in paths

Per a recent change to the URL spec, arbitrary %2e sequences
in URL paths that are not single or double dot segments are
not to be decoded.

Refs: https://github.com/whatwg/url/issues/87
Refs: https://github.com/whatwg/url/pull/156
Refs: https://github.com/w3c/web-platform-tests/commit/d93247d5cb7d70f80da8b154a171f4e3d50969f4
Fixes: https://github.com/nodejs/node/issues/10598
PR-URL: https://github.com/nodejs/node/pull/10602


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