fix error listener handler case

Port of nodejs/node@a62ff6d

Author: goto-bus-stop

events.js

@@ -461,7 +461,9 @@ function once(emitter, name) {
     };
 
     eventTargetAgnosticAddListener(emitter, name, resolver, { once: true });
-    addErrorHandlerIfEventEmitter(emitter, errorListener, { once: true });
+    if (name !== 'error') {
+      addErrorHandlerIfEventEmitter(emitter, errorListener, { once: true });
+    }
   });
 }
 

tests/events-once.js

@@ -134,7 +134,9 @@ function onceError() {
     ee.emit('error', expected);
   });
 
-  return once(ee, 'error').then(function (args) {
+  var promise = once(ee, 'error');
+  assert.strictEqual(ee.listenerCount('error'), 1);
+  return promise.then(function (args) {
     var err = args[0]
     assert.strictEqual(err, expected);
     assert.strictEqual(ee.listenerCount('error'), 0);