[minor] Skip unnecessary operations if the socket is already closed

There is no need to remove the already removed `socketOnData` listener,
resume the socket, and call `websocket.close()` if the socket is already
closed.

lib/websocket.js

@@ -918,13 +918,15 @@ function sendAfterClose(websocket, data, cb) {
 function receiverOnConclude(code, reason) {
   const websocket = this[kWebSocket];
 
-  websocket._socket.removeListener('data', socketOnData);
-  process.nextTick(resume, websocket._socket);
-
   websocket._closeFrameReceived = true;
   websocket._closeMessage = reason;
   websocket._closeCode = code;
 
+  if (websocket._socket[kWebSocket] === undefined) return;
+
+  websocket._socket.removeListener('data', socketOnData);
+  process.nextTick(resume, websocket._socket);
+
   if (code === 1005) websocket.close();
   else websocket.close(code, reason);
 }
@@ -947,15 +949,18 @@ function receiverOnDrain() {
 function receiverOnError(err) {
   const websocket = this[kWebSocket];
 
-  websocket._socket.removeListener('data', socketOnData);
+  if (websocket._socket[kWebSocket] !== undefined) {
+    websocket._socket.removeListener('data', socketOnData);
 
-  //
-  // On Node.js < 14.0.0 the `'error'` event is emitted synchronously. See
-  // https://github.com/websockets/ws/issues/1940.
-  //
-  process.nextTick(resume, websocket._socket);
+    //
+    // On Node.js < 14.0.0 the `'error'` event is emitted synchronously. See
+    // https://github.com/websockets/ws/issues/1940.
+    //
+    process.nextTick(resume, websocket._socket);
+
+    websocket.close(err[kStatusCode]);
+  }
 
-  websocket.close(err[kStatusCode]);
   websocket.emit('error', err);
 }