Check in codegen test expectations.

test/codegen/expect/corelib/main_test.js

Index: test/codegen/expect/corelib/main_test.js
diff --git a/test/codegen/expect/corelib/main_test.js b/test/codegen/expect/corelib/main_test.js
new file mode 100644
index 0000000000000000000000000000000000000000..a9a15d6084523e60c2e5a3194215a270de319d18
--- /dev/null
+++ b/test/codegen/expect/corelib/main_test.js
@@ -0,0 +1,19 @@
+dart_library.library('corelib/main_test', null, /* Imports */[
+  'dart_sdk',
+  'expect'
+], function load__main_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 main_test = Object.create(null);
+  let ListOfString = () => (ListOfString = dart.constFn(core.List$(core.String)))();
+  let ListOfStringTodynamic = () => (ListOfStringTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [ListOfString()])))();
+  main_test.main = function(args) {
+    expect$.Expect.equals(0, args[dartx.length]);
+  };
+  dart.fn(main_test.main, ListOfStringTodynamic());
+  // Exports:
+  exports.main_test = main_test;
+});