build: respect the `NODE` env variable in `Makefile`
In particular, what I'd like is to be able to do NODE=/path/to/some/specific/bin/node make test-doc -j.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
In particular, what I'd like is to be able to do NODE=/path/to/some/specific/bin/node make test-doc -j.