[libcxx][test] Silence MSVC narrowing warning

GitOrigin-RevId: 605751790418ca4fb1df1e94dfbac34cfcc1b96f
diff --git a/test/std/utilities/function.objects/func.search/func.search.default/default.pred.pass.cpp b/test/std/utilities/function.objects/func.search/func.search.default/default.pred.pass.cpp
index 59e5f7f..8ad0fe3 100644
--- a/test/std/utilities/function.objects/func.search/func.search.default/default.pred.pass.cpp
+++ b/test/std/utilities/function.objects/func.search/func.search.default/default.pred.pass.cpp
@@ -53,8 +53,8 @@
     int count = 0;
     std::default_searcher<Iter2, count_equal> s{b2, e2, count_equal{&count}};
     assert(result == std::search(b1, e1, s));
-    int d1 = std::distance(b1, e1);
-    int d2 = std::distance(b2, e2);
+    auto d1 = std::distance(b1, e1);
+    auto d2 = std::distance(b2, e2);
     assert((count >= 1) || (d2 == 0) || (d1 < d2));
     assert((d1 < d2) || count <= d1 * (d1 - d2 + 1));
 }