emit after 'error' #28710

I believe the events allowed to be emitted after error should be rather limited.

Based on the test suite I've found the following exceptions:

• exit, disconnect and close, should be ok.
• unpipe, maybe ok?

I've fixed some:

#28709
#28708
#28711

Then there are a lot of possible cases that might need fixing:

https://gist.github.com/ronag/b5728ae5db305abaff9955da5b47a5c9

I've found these by updating EventEmitter.prototype.emit with:

  if (this._emittedError) {
    if (!['close', 'exit', 'disconnect'].includes(type)) {
      throw new Error("unexpected event: " + type);
    }
  } else if (type === 'error') {
    this._emittedError = true;
  }

Is this worth to further look into?