Check in codegen test expectations.

test/codegen/expect/language/regress_18435_test.js

+dart_library.library('language/regress_18435_test', null, /* Imports */[
+  'dart_sdk',
+  'expect'
+], function load__regress_18435_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 regress_18435_test = Object.create(null);
+  let __Tovoid = () => (__Tovoid = dart.constFn(dart.definiteFunctionType(dart.void, [], [dart.dynamic, dart.dynamic])))();
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  regress_18435_test.main = function() {
+    let MISSING_VALUE = "MISSING_VALUE";
+    function foo(p1, p2) {
+      if (p1 === void 0) p1 = MISSING_VALUE;
+      if (p2 === void 0) p2 = MISSING_VALUE;
+      expect$.Expect.equals("P1", p1);
+      expect$.Expect.equals("P2", p2);
+    }
+    dart.fn(foo, __Tovoid());
+    function bar(p1, p2) {
+      if (p1 === void 0) p1 = "MISSING_VALUE";
+      if (p2 === void 0) p2 = "MISSING_VALUE";
+      expect$.Expect.equals("P1", p1);
+      expect$.Expect.equals("P2", p2);
+    }
+    dart.fn(bar, __Tovoid());
+    foo("P1", "P2");
+    bar("P1", "P2");
+  };
+  dart.fn(regress_18435_test.main, VoidTodynamic());
+  // Exports:
+  exports.regress_18435_test = regress_18435_test;
+});