test: deflake test-http-regr-nodejsgh-2928

The socket might take some time to connect. Call `parser.consume()` when
the connection is established.

Closes: nodejs#49565

Author: lpinca

test/sequential/test-http-regr-gh-2928.js

@@ -39,7 +39,9 @@ function execAndClose() {
     throw e;
   });
 
-  parser.consume(socket._handle);
+  socket.on('connect', function() {
+    parser.consume(socket._handle);
+  });
 
   parser.onIncoming = function onIncoming() {
     process.stdout.write('+');