Check in codegen test expectations.

test/codegen/expect/language/metadata_self_test.js

+dart_library.library('language/metadata_self_test', null, /* Imports */[
+  'dart_sdk'
+], function load__metadata_self_test(exports, dart_sdk) {
+  'use strict';
+  const core = dart_sdk.core;
+  const dart = dart_sdk.dart;
+  const dartx = dart_sdk.dartx;
+  const metadata_self_test = Object.create(null);
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  metadata_self_test.Foo = class Foo extends core.Object {
+    new() {
+    }
+  };
+  dart.setSignature(metadata_self_test.Foo, {
+    constructors: () => ({new: dart.definiteFunctionType(metadata_self_test.Foo, [])})
+  });
+  let const$;
+  metadata_self_test.main = function() {
+    let f = const$ || (const$ = dart.const(new metadata_self_test.Foo()));
+  };
+  dart.fn(metadata_self_test.main, VoidTodynamic());
+  // Exports:
+  exports.metadata_self_test = metadata_self_test;
+});