Check in codegen test expectations.

test/codegen/expect/language/raw_string_test.js

+dart_library.library('language/raw_string_test', null, /* Imports */[
+  'dart_sdk',
+  'expect'
+], function load__raw_string_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 raw_string_test = Object.create(null);
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  raw_string_test.RawStringTest = class RawStringTest extends core.Object {
+    static testMain() {
+      expect$.Expect.equals("abcd", "abcd");
+      expect$.Expect.equals("", "");
+      expect$.Expect.equals("", '');
+      expect$.Expect.equals("", "");
+      expect$.Expect.equals("", '');
+      expect$.Expect.equals("''''", "''''");
+      expect$.Expect.equals('""""', '""""');
+      expect$.Expect.equals("1\n2\n3", "1\n2\n3");
+      expect$.Expect.equals("1\n2\n3", '1\n2\n3');
+      expect$.Expect.equals("1", "1");
+      expect$.Expect.equals("1", '1');
+      expect$.Expect.equals("'", "'");
+      expect$.Expect.equals('"', '"');
+      expect$.Expect.equals("1", "1");
+      expect$.Expect.equals("1", "1");
+      expect$.Expect.equals("$", "$");
+      expect$.Expect.equals("\\", "\\");
+      expect$.Expect.equals("\\", '\\');
+      expect$.Expect.equals("${12}", "${12}");
+      expect$.Expect.equals("\\a\\b\\c\\d\\e\\f\\g\\h\\i\\j\\k\\l\\m", "\\a\\b\\c\\d\\e\\f\\g\\h\\i\\j\\k\\l\\m");
+      expect$.Expect.equals("\\n\\o\\p\\q\\r\\s\\t\\u\\v\\w\\x\\y\\z", "\\n\\o\\p\\q\\r\\s\\t\\u\\v\\w\\x\\y\\z");
+    }
+  };
+  dart.setSignature(raw_string_test.RawStringTest, {
+    statics: () => ({testMain: dart.definiteFunctionType(dart.dynamic, [])}),
+    names: ['testMain']
+  });
+  raw_string_test.main = function() {
+    raw_string_test.RawStringTest.testMain();
+  };
+  dart.fn(raw_string_test.main, VoidTodynamic());
+  // Exports:
+  exports.raw_string_test = raw_string_test;
+});