Replace all sort with unstable sort (#38427)

["When applicable, unstable sorting is preferred because it is generally
faster than stable sorting and it doesn’t allocate auxiliary
memory."](https://doc.rust-lang.org/std/vec/struct.Vec.html#method.sort)

Binary also reduced by 1KB in Release.

Testing: No behaviour change as semantically all current usage does not
have any pair with `std::cmp::Ordering::Equal`.

Signed-off-by: Euclid Ye <euclid.ye@huawei.com>

components/compositing/webview_manager.rs

@@ -127,7 +127,7 @@ mod test {
         webviews: &WebViewManager<WebView>,
     ) -> Vec<(WebViewId, WebView)> {
         let mut keys = webviews.webviews.keys().collect::<Vec<_>>();
-        keys.sort();
+        keys.sort_unstable();
         keys.iter()
             .map(|&id| (*id, webviews.webviews.get(id).cloned().unwrap()))
             .collect()