[es6] Fix invalid ToString in implementation of ToName.

src/full-codegen/arm/full-codegen-arm.cc

Index: src/full-codegen/arm/full-codegen-arm.cc
diff --git a/src/full-codegen/arm/full-codegen-arm.cc b/src/full-codegen/arm/full-codegen-arm.cc
index a6f658f455e98fc7067dfddc5e1de2605c914014..d354ec9d43e6830348f9061b4a83a1b765eeac43 100644
--- a/src/full-codegen/arm/full-codegen-arm.cc
+++ b/src/full-codegen/arm/full-codegen-arm.cc
@@ -3804,8 +3804,8 @@ void FullCodeGenerator::EmitToName(CallRuntime* expr) {
   __ CompareObjectType(r0, r1, r1, LAST_NAME_TYPE);
   __ b(ls, &done_convert);
   __ bind(&convert);
-  ToStringStub stub(isolate());
-  __ CallStub(&stub);
+  __ Push(r0);
+  __ CallRuntime(Runtime::kToName, 1);
   __ bind(&done_convert);
   context()->Plug(r0);
 }