http: suppress data event if req aborted

Re-enable test-http-abort-stream-end and put it into parallel
category. Use system random port when calling server.listen()
and fix eslint errors.

After calling request.abort(), in order to avoid the buffered
data to trigger the 'data' event, explicitly remove 'data' event
listeners.

lib/_http_incoming.js

@@ -314,6 +314,9 @@ function _addHeaderLine(field, value, dest) {
 IncomingMessage.prototype._dump = function _dump() {
   if (!this._dumped) {
     this._dumped = true;
+    // If there is buffered data, it may trigger 'data' events.
+    // Remove 'data' event listeners explicitly.
+    this.removeAllListeners('data');
     this.resume();
   }
 };

test/disabled/test-http-abort-stream-end.js → test/parallel/test-http-abort-stream-end.js

@@ -20,27 +20,27 @@
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 'use strict';
-const common = require('../common');
+require('../common');
 const assert = require('assert');
 
 const http = require('http');
 
-var maxSize = 1024;
-var size = 0;
+const maxSize = 1024;
+let size = 0;
 
-var s = http.createServer(function(req, res) {
+const s = http.createServer(function(req, res) {
   this.close();
 
   res.writeHead(200, {'Content-Type': 'text/plain'});
-  for (var i = 0; i < maxSize; i++) {
+  for (let i = 0; i < maxSize; i++) {
     res.write('x' + i);
   }
   res.end();
 });
 
-var aborted = false;
-s.listen(common.PORT, function() {
-  var req = http.get('http://localhost:' + common.PORT, function(res) {
+let aborted = false;
+s.listen(0, function() {
+  const req = http.get('http://localhost:' + s.address().port, function(res) {
     res.on('data', function(chunk) {
       size += chunk.length;
       assert(!aborted, 'got data after abort');
@@ -51,8 +51,6 @@ s.listen(common.PORT, function() {
       }
     });
   });
-
-  req.end();
 });
 
 process.on('exit', function() {