[turbofan] Work-around untagged result of CompareIC in pointer maps.

src/compiler/linkage.h

Index: src/compiler/linkage.h
diff --git a/src/compiler/linkage.h b/src/compiler/linkage.h
index a4b587dc4499407ec711d7896d70ed21d9b94736..c1f37626550978733f8fc6443e04960b6ed3a2fb 100644
--- a/src/compiler/linkage.h
+++ b/src/compiler/linkage.h
@@ -191,7 +191,8 @@ class Linkage : public ZoneObject {
   static CallDescriptor* GetStubCallDescriptor(
       Isolate* isolate, Zone* zone, const CallInterfaceDescriptor& descriptor,
       int stack_parameter_count, CallDescriptor::Flags flags,
-      Operator::Properties properties = Operator::kNoProperties);
+      Operator::Properties properties = Operator::kNoProperties,
+      MachineType return_type = kMachAnyTagged);
 
   // Creates a call descriptor for simplified C calls that is appropriate
   // for the host platform. This simplified calling convention only supports