http: remove default 'drain' listener on upgrade

Ensure that the default `'drain'` listener is removed before the
`'connect'` or `'upgrade'` event is emitted.

PR-URL: nodejs#18866
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

lib/_http_client.js

@@ -37,7 +37,7 @@ const { OutgoingMessage } = require('_http_outgoing');
 const Agent = require('_http_agent');
 const { Buffer } = require('buffer');
 const { urlToOptions, searchParamsSymbol } = require('internal/url');
-const { outHeadersKey } = require('internal/http');
+const { outHeadersKey, ondrain } = require('internal/http');
 const { nextTick } = require('internal/process/next_tick');
 const errors = require('internal/errors');
 
@@ -456,6 +456,7 @@ function socketOnData(d) {
 
     socket.removeListener('data', socketOnData);
     socket.removeListener('end', socketOnEnd);
+    socket.removeListener('drain', ondrain);
     parser.finish();
     freeParser(parser, req, socket);
 

test/parallel/test-http-connect.js

@@ -67,6 +67,7 @@ server.listen(0, common.mustCall(() => {
     assert.strictEqual(socket._httpMessage, null);
     assert.strictEqual(socket.listeners('connect').length, 0);
     assert.strictEqual(socket.listeners('data').length, 0);
+    assert.strictEqual(socket.listeners('drain').length, 0);
 
     // the stream.Duplex onend listener
     // allow 0 here, so that i can run the same test on streams1 impl