Check in codegen test expectations.

test/codegen/expect/language/prefix_new_test.js

+dart_library.library('language/prefix_new_test', null, /* Imports */[
+  'dart_sdk',
+  'expect'
+], function load__prefix_new_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 prefix_new_test = Object.create(null);
+  const prefix_test1 = Object.create(null);
+  const prefix_test2 = Object.create(null);
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  prefix_new_test.main = function() {
+    expect$.Expect.equals(prefix_test1.Prefix.getSource(), dart.dsend(prefix_test1.Prefix.getImport(), '+', 1));
+  };
+  dart.fn(prefix_new_test.main, VoidTodynamic());
+  prefix_test1.Prefix = class Prefix extends core.Object {
+    static getSource() {
+      return prefix_test1.Prefix.foo;
+    }
+    static getImport() {
+      return prefix_test2.Prefix.foo;
+    }
+  };
+  dart.setSignature(prefix_test1.Prefix, {
+    statics: () => ({
+      getSource: dart.definiteFunctionType(dart.dynamic, []),
+      getImport: dart.definiteFunctionType(dart.dynamic, [])
+    }),
+    names: ['getSource', 'getImport']
+  });
+  prefix_test1.Prefix.foo = 43;
+  prefix_test2.Prefix = class Prefix extends core.Object {};
+  prefix_test2.Prefix.foo = 42;
+  // Exports:
+  exports.prefix_new_test = prefix_new_test;
+  exports.prefix_test1 = prefix_test1;
+  exports.prefix_test2 = prefix_test2;
+});