[test] Fix unused variable in cctest loop

Change-Id: Ia574baaa796f1b2d6feea3e76364c9c417fb8ceb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3571899
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79808}

test/cctest/cctest.cc

@@ -336,8 +336,8 @@ i::Handle<i::JSFunction> Optimize(
 }
 
 static void PrintTestList() {
-  for (auto [name, test] : g_cctests.Get()) {
-    printf("%s\n", name.c_str());
+  for (const auto& entry : g_cctests.Get()) {
+    printf("%s\n", entry.first.c_str());
   }
 }