test: add flaky test for investigation

Refs: nodejs#49574 (comment)
Refs: nodejs#49574 (comment)

test/sequential/test-net-gh-49574.js

@@ -0,0 +1,42 @@
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+const net = require('net');
+
+const COUNT = 1000 + 1;
+let gotResponses = 0;
+
+const response = Buffer.from('HTTP/1.1 200 OK\r\n\r\n');
+
+function execAndClose() {
+  process.stdout.write('.');
+
+  const chunks = [];
+  const socket = net.connect(common.PORT);
+
+  socket.on('end', socket.end);
+  socket.on('connect', function() {
+    process.stdout.write('c');
+  });
+  socket.on('data', function(chunk) {
+    process.stdout.write('d');
+    chunks.push(chunk);
+  });
+  socket.on('close', function() {
+    assert.deepStrictEqual(Buffer.concat(chunks), response);
+
+    if (++gotResponses === COUNT) {
+      server.close();
+    } else {
+      execAndClose();
+    }
+  });
+}
+
+const server = net.createServer(function(socket) {
+  socket.end(response);
+  socket.resume();
+});
+
+server.listen(common.PORT, common.mustCall(execAndClose));