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

test/cctest/compiler/graph-builder-tester.h

Index: test/cctest/compiler/graph-builder-tester.h
diff --git a/test/cctest/compiler/graph-builder-tester.h b/test/cctest/compiler/graph-builder-tester.h
index de7d20c34b4d2f59d7a6682df05019eb81be1122..077b71f17b7c85d405cbc395d1ddbaf5890cb73a 100644
--- a/test/cctest/compiler/graph-builder-tester.h
+++ b/test/cctest/compiler/graph-builder-tester.h
@@ -104,8 +104,7 @@ class GraphBuilderTester : public HandleAndZoneScope,
     return NewNode(common()->Int32Constant(value));
   }
   Node* HeapConstant(Handle<HeapObject> object) {
-    Unique<HeapObject> val = Unique<HeapObject>::CreateUninitialized(object);
-    return NewNode(common()->HeapConstant(val));
+    return NewNode(common()->HeapConstant(object));
   }
 
   Node* BooleanNot(Node* a) { return NewNode(simplified()->BooleanNot(), a); }