console,util: avoid pair array generation in C++

Use a plain `[key, value, key, value]`-style list instead
of an array of pairs for inspecting collections.

This also fixes a bug with `console.table()` where
inspecting a non-key-value `MapIterator` would have
led to odd results.

PR-URL: https://github.com/nodejs/node/pull/20831
Refs: https://github.com/nodejs/node/pull/20719#discussion_r189342513


Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Minwoo Jung <minwoo@nodesource.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>