assert: add strict functionality export

Requireing the strict version will allow to use `assert.equal`,
`assert.deepEqual` and there negated counterparts to be used with
strict comparison instead of using e.g. `assert.strictEqual`.

The API is identical to the regular assert export and only differs
in the way that all functions use strict compairson.

PR-URL: https://github.com/nodejs/node/pull/17002


Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>