Events polyfill is not up to date with latest version of Node.js

The events.js polyfill is not up to date with the latest Node.js

For example, the polyfill is missing the EventEmitter.prototype.off method. This was introduced to node in version 10.0.0 (see https://nodejs.org/dist/latest-v14.x/docs/api/events.html#events_emitter_off_eventname_listener)

Start by inspecting the events.js polyfill and compare its EventEmitter API with the Node.js events documentation linked in the issue. Confirm how EventEmitter.prototype.off should behave, then update the polyfill and verify that the compatibility behavior is covered by the repository's existing checks.

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