util: change %o depth default

Since the default for depth is changed to `Infinity` it is logical
to change the %o default to the same as well.

Using %o with `util.format` will now always print the whole object.

PR-URL: https://github.com/nodejs/node/pull/17907
Refs: https://github.com/nodejs/node/issues/12693


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>