dart2js cps: Make Identical a built-in and add Interceptor to Tree IR.

pkg/compiler/lib/src/js_backend/codegen/unsugar.dart

 library dart2js.unsugar_cps;
 
 import '../../cps_ir/cps_ir_nodes.dart';
 
 import '../../cps_ir/optimizers.dart' show ParentVisitor;
 import '../../constants/expressions.dart';
 import '../../constants/values.dart';
 import '../../elements/elements.dart' show
     ClassElement,
     FieldElement,
@@ skipping 107 matching lines @@
     originalBody.body = function.body;
 
     Continuation returnFalse = new Continuation(<Parameter>[]);
     Primitive falsePrimitive = falseConstant;
     returnFalse.body =
         new LetPrim(falsePrimitive,
             new InvokeContinuation(
                 function.returnContinuation, <Primitive>[falsePrimitive]));
 
     Primitive nullPrimitive = nullConstant;
-    Primitive test = new Identical(function.parameters.single, nullPrimitive);
+    Primitive test = new ApplyBuiltinOperator(
+        BuiltinOperator.Identical,
+          <Primitive>[function.parameters.single, nullPrimitive]);
 
     Expression newBody =
         new LetCont.many(<Continuation>[returnFalse, originalBody],
             new LetPrim(nullPrimitive,
                 new LetPrim(test,
                     new Branch(
                         new IsTrue(test),
                         returnFalse,
                         originalBody))));
     function.body = newBody;
@@ skipping 124 matching lines @@
       // `this`), not `null`.
       node.receiver = new Reference<Primitive>(nullPrim);
     }
   }
 
   processBranch(Branch node) {
     // TODO(karlklose): implement the checked mode part of boolean conversion.
     InteriorNode parent = node.parent;
     IsTrue condition = node.condition;
     Primitive t = trueConstant;
-    Primitive i = new Identical(condition.value.definition, t);
+    Primitive i = new ApplyBuiltinOperator(
+        BuiltinOperator.Identical,
+        <Primitive>[condition.value.definition, t]);
     LetPrim newNode = new LetPrim(t,
         new LetPrim(i,
             new Branch(new IsTrue(i),
                 node.trueContinuation.definition,
                 node.falseContinuation.definition)));
     condition.value.unlink();
     node.trueContinuation.unlink();
     node.falseContinuation.unlink();
     parent.body = newNode;
   }
 
   processInterceptor(Interceptor node) {
     _glue.registerSpecializedGetInterceptor(node.interceptedClasses);
   }
 }