[turbofan] Remove usage of Unique<T> from graph.

test/cctest/compiler/test-js-constant-cache.cc

Index: test/cctest/compiler/test-js-constant-cache.cc
diff --git a/test/cctest/compiler/test-js-constant-cache.cc b/test/cctest/compiler/test-js-constant-cache.cc
index 8774a9a9e36c3b740bcd970ec101c7c1382486a8..f4120b050bef365e5a6326cc9a3870f1820fa08b 100644
--- a/test/cctest/compiler/test-js-constant-cache.cc
+++ b/test/cctest/compiler/test-js-constant-cache.cc
@@ -47,9 +47,9 @@ class JSConstantCacheTester : public HandleAndZoneScope,
 
   Type* upper(Node* node) { return NodeProperties::GetBounds(node).upper; }
 
-  Handle<Object> handle(Node* node) {
+  Handle<HeapObject> handle(Node* node) {
     CHECK_EQ(IrOpcode::kHeapConstant, node->opcode());
-    return OpParameter<Unique<Object> >(node).handle();
+    return OpParameter<Handle<HeapObject>>(node);
   }
 
   Factory* factory() { return main_isolate()->factory(); }