test: move platform-server integration test (#22810)

Now it lives in our standard location for tests against npm packages

PR Close #22810

integration/platform-server/webpack.server.config.js

@@ -0,0 +1,14 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+module.exports = {
+  target: 'node',
+  entry: './built/src/server.js',
+  output: {filename: './built/server-bundle.js'},
+  resolve: {extensions: ['.js']},
+};