Fix missing directives in test example

Author: jieyouxu

posts/inside-rust/2024-11-04-test-infra-oct-2024-2.md

@@ -75,6 +75,10 @@ Example usage:
 ```rs
 // tests/ui/abi/my-abi-test.rs
 
+//@ add-core-stubs
+//@ compile-flags: --target x86_64-pc-windows-msvc
+//@ needs-llvm-components: x86
+
 #![crate_type = "lib"]
 #![feature(no_core)]
 #![no_std]