Add Node DNS module to empty mocks

[Downchuck]

DNS is required by some popular node.js modules; presently a require statement for DNS will throw an error if it is not wrapped in a try catch block.

Closes#6277.

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[Downchuck]

This PR came from this conversation:
#6277

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[Downchuck]

seems like this failed for unrelated reasons (build broken?)

[mrmckeb]

Yes, this is not related to your work @Downchuck.