Support serialization of all resolved asts from dart:core

pkg/compiler/lib/src/cps_ir/cps_ir_builder_task.dart

Index: pkg/compiler/lib/src/cps_ir/cps_ir_builder_task.dart
diff --git a/pkg/compiler/lib/src/cps_ir/cps_ir_builder_task.dart b/pkg/compiler/lib/src/cps_ir/cps_ir_builder_task.dart
index e8f72b2bce9f7b73dcb7db70e91bd71249f43e74..db163585750b3e2a702be97bb4e96458c3d31b4a 100644
--- a/pkg/compiler/lib/src/cps_ir/cps_ir_builder_task.dart
+++ b/pkg/compiler/lib/src/cps_ir/cps_ir_builder_task.dart
@@ -2267,7 +2267,7 @@ class IrBuilderVisitor extends ast.Visitor<ir.Primitive>
       // libraries contain a dummy const constructor implementation that
       // doesn't perform validation and the compiler compiles a call to
       // (non-const) Symbol.validated when it sees new Symbol(...).
-      target = compiler.symbolValidatedConstructor;
+      target = helpers.symbolValidatedConstructor;
     } else {
       target = constructor.implementation;
     }