Check in codegen test expectations.

test/codegen/expect/language/issue10561_test.js

Index: test/codegen/expect/language/issue10561_test.js
diff --git a/test/codegen/expect/language/issue10561_test.js b/test/codegen/expect/language/issue10561_test.js
new file mode 100644
index 0000000000000000000000000000000000000000..fd3088e4c3a01574d7a7a123b17f01de2af70841
--- /dev/null
+++ b/test/codegen/expect/language/issue10561_test.js
@@ -0,0 +1,24 @@
+dart_library.library('language/issue10561_test', null, /* Imports */[
+  'dart_sdk',
+  'expect'
+], function load__issue10561_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 issue10561_test = Object.create(null);
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  issue10561_test.Foo = class Foo extends core.Expando {
+    new() {
+      super.new();
+    }
+  };
+  dart.addSimpleTypeTests(issue10561_test.Foo);
+  issue10561_test.main = function() {
+    expect$.Expect.isNull(new issue10561_test.Foo().get(new core.Object()));
+  };
+  dart.fn(issue10561_test.main, VoidTodynamic());
+  // Exports:
+  exports.issue10561_test = issue10561_test;
+});