move conditional compilation attribute to include the whole test module

src/unistd.rs

@@ -2753,13 +2753,13 @@ impl Group {
 }
 
 
+#[cfg(any(target_os = "linux", target_os = "android"))]
 #[cfg(test)]
 mod tests {
     use super::*;
     use std::{fs, thread, io};
 
     /// Tests setting the filesystem UID with `setfsuid`.
-    #[cfg(any(target_os = "linux", target_os = "android"))]
     #[test]
     fn test_setfsuid() {
         use std::os::unix::fs::PermissionsExt;