Check in codegen test expectations.

test/codegen/expect/script.js

Index: test/codegen/expect/script.js
diff --git a/test/codegen/expect/script.js b/test/codegen/expect/script.js
new file mode 100644
index 0000000000000000000000000000000000000000..ae13313f1074df2fcea0c5a94fa36a75ae4123b8
--- /dev/null
+++ b/test/codegen/expect/script.js
@@ -0,0 +1,19 @@
+dart_library.library('script', null, /* Imports */[
+  'dart_sdk'
+], function load__script(exports, dart_sdk) {
+  'use strict';
+  const core = dart_sdk.core;
+  const dart = dart_sdk.dart;
+  const dartx = dart_sdk.dartx;
+  const script = Object.create(null);
+  let ListOfString = () => (ListOfString = dart.constFn(core.List$(core.String)))();
+  let ListOfStringTovoid = () => (ListOfStringTovoid = dart.constFn(dart.definiteFunctionType(dart.void, [ListOfString()])))();
+  script.main = function(args) {
+    let name = args[dartx.join](' ');
+    if (name == '') name = 'world';
+    core.print(dart.str`hello ${name}`);
+  };
+  dart.fn(script.main, ListOfStringTovoid());
+  // Exports:
+  exports.script = script;
+});