Support Deno?

[DerekNonGeneric]

I was chatting with @andreubotella about the Deno implementation of the atob and btoa globals specified by Web IDL (et al.) when it occurred to me that it would be convenient if it were possible to use this tool to facilitate efforts towards interop. It could potentially help us work towards spec-compliance and conformance w/ other server-side scripting hosts. Avoiding divergence between the two by being able to quickly check Deno behavior against Node seems useful (if it would qualify) and may spur further interop activities.

https://github.com/denoland/deno/