test: Fix unused imports by moving them inside the cfg-gated test

tests/repro_old423.rs

@@ -1,13 +1,12 @@
-use std::env::temp_dir;
-use std::io;
-use zip::result::ZipResult;
-use zip::ZipArchive;
-
 #[cfg(all(unix, feature = "_deflate-any"))]
 #[test]
-fn repro_old423() -> ZipResult<()> {
+fn repro_old423() -> zip::result::ZipResult<()> {
+    use std::env::temp_dir;
+    use std::io;
+    use zip::ZipArchive;
+
     let mut v = Vec::new();
     v.extend_from_slice(include_bytes!("data/lin-ub_iwd-v11.zip"));
     let mut archive = ZipArchive::new(io::Cursor::new(v)).expect("couldn't open test zip file");
     archive.extract(temp_dir())
-}
+}