Refactor: optimize println!()

Clippy 1.58.0 complains about `format!()` inside `println!()` being
inefficient

boa_tester/src/results.rs

@@ -253,11 +253,9 @@ pub(crate) fn compare_results(base: &Path, new: &Path, markdown: bool) {
             diff_format(panic_diff),
         );
         println!(
-            "| Conformance | {:.2}% | {:.2}% | {} |",
+            "| Conformance | {:.2}% | {:.2}% | {}{}{:.2}%{} |",
             base_conformance,
             new_conformance,
-            format!(
-                "{}{}{:.2}%{}",
             if conformance_diff.abs() > f64::EPSILON {
                 "**"
             } else {
@@ -270,7 +268,6 @@ pub(crate) fn compare_results(base: &Path, new: &Path, markdown: bool) {
             } else {
                 ""
             },
-            ),
         );
 
         if !test_diff.fixed.is_empty() {