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

src/builtins/builtins-math.cc

Index: src/builtins/builtins-math.cc
diff --git a/src/builtins/builtins-math.cc b/src/builtins/builtins-math.cc
index 3cf0d90d30cd6a3347266164ade849329f0fafc5..58e2601766721c1ff884249949730b5ff0dda1ee 100644
--- a/src/builtins/builtins-math.cc
+++ b/src/builtins/builtins-math.cc
@@ -364,7 +364,7 @@ BUILTIN(MathHypot) {
   bool one_arg_is_nan = false;
   List<double> abs_values(length);
   for (int i = 0; i < length; i++) {
-    Handle<Object> x = args.at<Object>(i + 1);
+    Handle<Object> x = args.at(i + 1);
     ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, x, Object::ToNumber(x));
     double abs_value = std::abs(x->Number());