url: update WHATWG URL API to latest spec

- Update to spec
  - Add opaque hosts
  - File state did not correctly deal with lack of base URL
  - Cleanup API for file and non-special URLs
  - Allow % and IPv6 addresses in non-special URL hosts
  - Use specific names for percent-encode sets
  - Add empty host concept for file and non-special URLs
  - Clarify IPv6 serializer
- Fix existing mistakes
  - Add missing ':' to forbidden host code point list.
  - Correct IPv4 parser empty label behavior
- Maintain type equivalence in URLContext with spec
  - scheme, username, and password should always be strings
  - host, port, query, and fragment may be strings or null
  - Align scheme state more closely with the spec
  - Make sure the `special` variable is always synced with
    URL_FLAG_SPECIAL.

PR-URL: https://github.com/nodejs/node/pull/12523
Fixes: https://github.com/nodejs/node/issues/10608
Fixes: https://github.com/nodejs/node/issues/10634
Refs: https://github.com/whatwg/url/pull/185
Refs: https://github.com/whatwg/url/pull/225
Refs: https://github.com/whatwg/url/pull/224
Refs: https://github.com/whatwg/url/pull/218
Refs: https://github.com/whatwg/url/pull/243
Refs: https://github.com/whatwg/url/pull/260
Refs: https://github.com/whatwg/url/pull/268


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Daijiro Wachi <daijiro.wachi@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>