Use final url for updating stylesheet from @import rule.

components/script/stylesheet_loader.rs

@@ -161,6 +161,7 @@ impl FetchResponseListener for StylesheetContext {
                                                   &data,
                                                   protocol_encoding_label,
                                                   Some(environment_encoding),
+                                                  &final_url,
                                                   Some(&loader),
                                                   win.css_error_reporter());
                 }