test: make HTTP/1.0 connection test more robust

Fixes: nodejs#47200

test/parallel/test-http-remove-connection-header-persists-connection.js

@@ -45,14 +45,20 @@ function makeHttp11Request(cb) {
 function makeHttp10Request(cb) {
   // We have to manually make HTTP/1.0 requests since Node does not allow sending them:
   const socket = net.connect({ port: server.address().port }, function() {
+    socket.on('error', common.mustNotCall());
+
     socket.write('GET / HTTP/1.0\r\n' +
                'Host: localhost:' + server.address().port + '\r\n' +
                 '\r\n');
-    socket.resume(); // Ignore the response itself
+    socket.end(); // we are done sending data
+    socket.resume();
 
-    setTimeout(function() {
-      cb(socket);
-    }, common.platformTimeout(50));
+    // Wait for response to be sent before invoking callback
+    socket.on('close', function() {
+      setTimeout(function() {
+        cb(socket);
+      }, common.platformTimeout(100));
+    });
   });
 }
 
@@ -63,7 +69,8 @@ server.listen(0, function() {
       assert.strictEqual(firstSocket, secondSocket);
 
       makeHttp10Request(function(socket) {
-        // The server should have immediately closed the HTTP/1.0 socket:
+        // We waited for the HTTP response above, so
+        // the server should have immediately closed the HTTP/1.0 socket:
         assert.strictEqual(socket.closed, true);
         server.close();
       });