url: check forEach callback is a function

The Web IDL spec mandates such a check.

Also make error messages consistent with rest of Node.js and add
additional tests for forEach().

PR-URL: https://github.com/nodejs/node/pull/10905


Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>