[runtime] Port simple String.prototype.indexOf cases to TF Builtin

src/runtime/runtime-function.cc

Index: src/runtime/runtime-function.cc
diff --git a/src/runtime/runtime-function.cc b/src/runtime/runtime-function.cc
index 7413f8750ae5d69648f15ac1b3dc04ac198daa60..9aba2a89c4fa57eda82d695c06b83235b1195d68 100644
--- a/src/runtime/runtime-function.cc
+++ b/src/runtime/runtime-function.cc
@@ -278,7 +278,7 @@ RUNTIME_FUNCTION(Runtime_Call) {
   CONVERT_ARG_HANDLE_CHECKED(Object, receiver, 1);
   ScopedVector<Handle<Object>> argv(argc);
   for (int i = 0; i < argc; ++i) {
-    argv[i] = args.at<Object>(2 + i);
+    argv[i] = args.at(2 + i);
   }
   RETURN_RESULT_OR_FAILURE(
       isolate, Execution::Call(isolate, target, receiver, argc, argv.start()));