build: produce metadata bundles for @angular modules (#14509)

Closes #14509

modules/@angular/upgrade/public_api_static.ts

@@ -0,0 +1,21 @@
+/**
+ * @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
+ * @description
+ * Entry point for all public APIs of the upgrade/static package, allowing
+ * Angular 1 and Angular 2+ to run side by side in the same application.
+ */
+export {downgradeComponent} from './src/common/downgrade_component';
+export {downgradeInjectable} from './src/common/downgrade_injectable';
+export {VERSION} from './src/common/version';
+export {UpgradeComponent} from './src/static/upgrade_component';
+export {UpgradeModule} from './src/static/upgrade_module';
+
+// This file only re-exports content of the `src` folder. Keep it that way.