Add ErrorEvent shim

Node.js lacks the [web standard `ErrorEvent`](https://developer.mozilla.org/en-US/docs/Web/API/ErrorEvent) which can be depended upon by some code (like oak). For a long time I have [been shimming it myself](https://github.com/oakserver/oak/blob/2adc5bc2a0b0fe086ee53d1252378f78563c8903/node_shims.ts#L3) but it feels like it could be useful as part of dnt [as others seem to be needing it as well](https://github.com/denoland/dnt/issues/14#issuecomment-1950960613).