bugfix(core): fix missing await in NestApplication.close()

NestApplication.close() was not always closing the port after promise resolve, because of the missing `await` in implementation. This commit fixes the problem.

Author: weekens

packages/core/nest-application.ts

@@ -222,7 +222,7 @@ export class NestApplication extends NestApplicationContext
 
   public async close(): Promise<any> {
     this.socketModule && (await this.socketModule.close());
-    this.httpAdapter && this.httpAdapter.close();
+    this.httpAdapter && (await this.httpAdapter.close());
 
     await Promise.all(
       iterate(this.microservices).map(async microservice => {