Check in codegen test expectations.

test/codegen/expect/language/optimized_isempty_test.js

+dart_library.library('language/optimized_isempty_test', null, /* Imports */[
+  'dart_sdk',
+  'expect'
+], function load__optimized_isempty_test(exports, dart_sdk, expect) {
+  'use strict';
+  const core = dart_sdk.core;
+  const _interceptors = dart_sdk._interceptors;
+  const dart = dart_sdk.dart;
+  const dartx = dart_sdk.dartx;
+  const expect$ = expect.expect;
+  const optimized_isempty_test = Object.create(null);
+  let JSArrayOfint = () => (JSArrayOfint = dart.constFn(_interceptors.JSArray$(core.int)))();
+  let dynamicTodynamic = () => (dynamicTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [dart.dynamic])))();
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  optimized_isempty_test.test = function(s) {
+    return dart.dload(s, 'isEmpty');
+  };
+  dart.fn(optimized_isempty_test.test, dynamicTodynamic());
+  optimized_isempty_test.main = function() {
+    let x = "abc";
+    let y = JSArrayOfint().of([123, 12345, 765]);
+    expect$.Expect.equals(false, optimized_isempty_test.test(x));
+    expect$.Expect.equals(false, optimized_isempty_test.test(y));
+    for (let i = 0; i < 20; i++)
+      optimized_isempty_test.test(x);
+    expect$.Expect.equals(false, optimized_isempty_test.test(x));
+    expect$.Expect.equals(false, optimized_isempty_test.test(y));
+  };
+  dart.fn(optimized_isempty_test.main, VoidTodynamic());
+  // Exports:
+  exports.optimized_isempty_test = optimized_isempty_test;
+});