assert: fix deepEqual similar sets and maps bug

This fixes a bug where deepEqual and deepStrictEqual would have
incorrect behaviour in sets and maps containing multiple equivalent
keys.

PR-URL: https://github.com/nodejs/node/pull/13426
Fixes: https://github.com/nodejs/node/issues/13347
Refs: https://github.com/nodejs/node/pull/12142


Reviewed-By: Refael Ackermann <refack@gmail.com>