module: add path to the module object

This adds the `path` property to the module object. It contains the
current directory as path. That is necessary to add an extra caching
layer.

It also makes sure the `id` uses a default in case it's not set.
Otherwise the `path.dirname(id)` command could fail.

PR-URL: https://github.com/nodejs/node/pull/26970
Refs: https://github.com/nodejs/node/pull/25362


Reviewed-By: Guy Bedford <guybedford@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>