Check in codegen test expectations.

test/codegen/expect/language/extends_test.js

+dart_library.library('language/extends_test', null, /* Imports */[
+  'dart_sdk',
+  'expect'
+], function load__extends_test(exports, dart_sdk, expect) {
+  'use strict';
+  const core = dart_sdk.core;
+  const dart = dart_sdk.dart;
+  const dartx = dart_sdk.dartx;
+  const expect$ = expect.expect;
+  const extends_test = Object.create(null);
+  const extends_test_lib = Object.create(null);
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  extends_test.A = class A extends core.Object {
+    new() {
+      this.y = "class A from main script";
+    }
+  };
+  extends_test.S = class S extends extends_test.A {
+    new() {
+      super.new();
+    }
+  };
+  extends_test.main = function() {
+    let s = new extends_test.S();
+    expect$.Expect.equals("class A from main script", s.y);
+  };
+  dart.fn(extends_test.main, VoidTodynamic());
+  extends_test_lib.A = class A extends core.Object {
+    new() {
+      this.y = "class A from library";
+    }
+  };
+  // Exports:
+  exports.extends_test = extends_test;
+  exports.extends_test_lib = extends_test_lib;
+});