Win64 - Allow returning two values from a runtime function.

src/codegen.cc

Index: src/codegen.cc
diff --git a/src/codegen.cc b/src/codegen.cc
index 8e516c0b04c5e06e5af4d9fc42e7c2a2b416b26a..9a00ae2b65d72f86c713b39aba80219251a5de43 100644
--- a/src/codegen.cc
+++ b/src/codegen.cc
@@ -517,7 +517,10 @@ const char* RuntimeStub::GetName() {
 
 
 void RuntimeStub::Generate(MacroAssembler* masm) {
-  masm->TailCallRuntime(ExternalReference(id_), num_arguments_);
+  Runtime::Function* f = Runtime::FunctionForId(id_);
+  masm->TailCallRuntime(ExternalReference(f),
+                        num_arguments_,
+                        f->result_size);
 }