Check in codegen test expectations.

test/codegen/expect/language/map_literal2_test.js

Index: test/codegen/expect/language/map_literal2_test.js
diff --git a/test/codegen/expect/language/map_literal2_test.js b/test/codegen/expect/language/map_literal2_test.js
new file mode 100644
index 0000000000000000000000000000000000000000..eb68ca95032eeb5eb4924dfb05f292be7ddb9cf8
--- /dev/null
+++ b/test/codegen/expect/language/map_literal2_test.js
@@ -0,0 +1,31 @@
+dart_library.library('language/map_literal2_test', null, /* Imports */[
+  'dart_sdk',
+  'expect'
+], function load__map_literal2_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 map_literal2_test = Object.create(null);
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  map_literal2_test.nextValCtr = null;
+  dart.copyProperties(map_literal2_test, {
+    get nextVal() {
+      let x = map_literal2_test.nextValCtr;
+      map_literal2_test.nextValCtr = dart.notNull(x) + 1;
+      return x;
+    }
+  });
+  map_literal2_test.main = function() {
+    map_literal2_test.nextValCtr = 0;
+    let map = dart.map({[dart.str`a${map_literal2_test.nextVal}`]: "Grey", [dart.str`a${map_literal2_test.nextVal}`]: "Poupon"});
+    expect$.Expect.equals(true, map[dartx.containsKey]("a0"));
+    expect$.Expect.equals(true, map[dartx.containsKey]("a1"));
+    expect$.Expect.equals("Grey", map[dartx.get]("a0"));
+    expect$.Expect.equals("Poupon", map[dartx.get]("a1"));
+  };
+  dart.fn(map_literal2_test.main, VoidTodynamic());
+  // Exports:
+  exports.map_literal2_test = map_literal2_test;
+});