Fix for node modules

test/codegen/expect/node_modules.js

-'use strict';
+(function() {
+  'use strict';
+  const dart_sdk = require('dart_sdk');
+  const core = dart_sdk.core;
+  const dart = dart_sdk.dart;
+  const dartx = dart_sdk.dartx;
+  const node_modules = Object.create(null);
+  node_modules.Callback = dart.typedef('Callback', () => dart.functionType(dart.void, [], {i: core.int}));
+  node_modules.A = class A extends core.Object {};
+  node_modules._A = class _A extends core.Object {};
+  node_modules.B$ = dart.generic(T => {
+    class B extends core.Object {}
+    return B;
+  });
+  node_modules.B = node_modules.B$();
+  node_modules._B$ = dart.generic(T => {
+    class _B extends core.Object {}
+    return _B;
+  });
+  node_modules._B = node_modules._B$();
+  node_modules.f = function() {
+  };
+  dart.fn(node_modules.f);
+  node_modules._f = function() {
+  };
+  dart.fn(node_modules._f);
+  node_modules.constant = "abc";
+  node_modules.finalConstant = "abc";
+  dart.defineLazy(node_modules, {
+    get lazy() {
+      return dart.fn(() => {
+        core.print('lazy');
+        return "abc";
+      }, core.String, [])();
+    }
+  });
+  node_modules.mutable = "abc";
+  dart.defineLazy(node_modules, {
+    get lazyMutable() {
+      return dart.fn(() => {
+        core.print('lazyMutable');
+        return "abc";
+      }, core.String, [])();
+    },
+    set lazyMutable(_) {}
+  });
+  // Exports:
+  exports.node_modules = node_modules;
+})();