test: remove duplicate test

`test/parallel/test-http-agent-no-wait.js` is basically a duplicate of
`test/parallel/test-http-client-close-with-default-agent.js`, remove it.

PR-URL: #44051
Reviewed-By: Paolo Insogna <paolo@cowtech.it>
Reviewed-By: Feng Yu <F3n67u@outlook.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

test/parallel/test-http-client-close-with-default-agent.js

@@ -0,0 +1,23 @@
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+const http = require('http');
+
+const server = http.createServer(function(req, res) {
+  res.writeHead(200);
+  res.end();
+});
+
+server.listen(0, common.mustCall(() => {
+  const req = http.get({ port: server.address().port }, (res) => {
+    assert.strictEqual(res.statusCode, 200);
+    res.resume();
+    server.close();
+  });
+
+  req.end();
+}));
+
+// This timer should never go off as the server will close the socket
+setTimeout(common.mustNotCall(), common.platformTimeout(1000)).unref();