Address review comments in commited cl (issue 10460002).

runtime/vm/code_generator_ia32.cc

Index: runtime/vm/code_generator_ia32.cc
===================================================================
--- runtime/vm/code_generator_ia32.cc	(revision 8115)
+++ runtime/vm/code_generator_ia32.cc	(working copy)
@@ -817,14 +817,16 @@
     ASSERT(!function.IsImplicitStaticClosureFunction());
     const bool kPushInstantiator = false;
     GenerateInstantiatorTypeArguments(node->token_index(), kPushInstantiator);
+  } else {
+    const Immediate raw_null =
+        Immediate(reinterpret_cast<intptr_t>(Object::null()));
+    __ pushl(raw_null);  // No type arguments.
   }
   const Code& stub = Code::Handle(
       StubCode::GetAllocationStubForClosure(function));
   const ExternalLabel label(function.ToCString(), stub.EntryPoint());
   GenerateCall(node->token_index(), &label, PcDescriptors::kOther);
-  if (requires_type_arguments) {
-    __ popl(ECX);  // Pop type arguments.
-  }
+  __ popl(ECX);  // Pop type arguments.
   if (function.IsImplicitInstanceClosureFunction()) {
     __ popl(ECX);  // Pop receiver.
   }