Fix switch-stdout test for none unix/windows platforms

Author: raoulstrackx

std/tests/switch-stdout.rs

@@ -1,4 +1,4 @@
-#[cfg(any(target_family = "unix", target_family = "windows"))]
+#![cfg(any(target_family = "unix", target_family = "windows"))]
 
 use std::fs::File;
 use std::io::{Read, Write};