Check for duplicate library names

test/codegen/expect/sunflower/circle.js

Index: test/codegen/expect/sunflower/circle.js
diff --git a/test/codegen/expect/sunflower/circle.js b/test/codegen/expect/sunflower/circle.js
index 698bf9ccb9f32619e8dcc6ff63339b9ac5dcf572..9fe464bcc4158b7bc8db4759ce561e6c28c67f8e 100644
--- a/test/codegen/expect/sunflower/circle.js
+++ b/test/codegen/expect/sunflower/circle.js
@@ -1,6 +1,7 @@
-var circle = dart.defineLibrary(circle, {});
-var core = dart.import(core);
-(function(exports, core) {
+dart.library('circle', null, /* Imports */[
+  'dart/core'
+], /* Lazy imports */[
+], function(exports, core) {
   'use strict';
   class Circle extends core.Object {
     Circle(x, y, radius) {
@@ -14,4 +15,4 @@ var core = dart.import(core);
   });
   // Exports:
   exports.Circle = Circle;
-})(circle, core);
+});