http: prevent aborted event when already completed

When socket is closed on a response for a request that is being piped to
a stream there is a condition where aborted event will be fired to http
client when socket is closing and the incomingMessage stream is still
set to readable.

We need a check for request being complete and to only raise the
'aborted' event on the http client if we have not yet completed reading
the response from the server.

Fixes: nodejs#18756

PR-URL: nodejs#18999
Reviewed-By: Shingo Inoue <leko.noor@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

lib/_http_client.js

@@ -321,7 +321,7 @@ function socketCloseListener() {
  var parser = socket.parser;
  if (req.res && req.res.readable) {
  // Socket closed before we emitted 'end' below.
- req.res.emit('aborted');
+ if (!req.res.complete) req.res.emit('aborted');
  var res = req.res;
  res.on('end', function() {
  res.emit('close');