Revert two Kernel changes that were causing test failures.

tests/language_2/assert_message_test.dart

-// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-import "dart:async";
-
-import "package:async_helper/async_helper.dart";
-import "package:expect/expect.dart";
-
-// TODO(rnystrom): Unify with assert_with_message_test.dart.
-
-main() {
-  // Only run with asserts enabled mode.
-  bool assertsEnabled = false;
-  assert(assertsEnabled = true);
-  if (!assertsEnabled) return;
-
-  // Basics.
-  assert(true, "");
-  assert(() => true, "");
-
-  int x = null;
-  // Successful asserts won't execute message.
-  assert(true, x + 42);
-  assert(true, throw "unreachable");
-
-  // Can use any value as message.
-  try {
-    assert(false, 42);
-  } on AssertionError catch (e) {
-    Expect.equals(42, e.message);
-  }
-
-  try {
-    assert(false, "");
-  } on AssertionError catch (e) {
-    Expect.equals("", e.message);
-  }
-
-  try {
-    assert(false, null);
-  } on AssertionError catch (e) {
-    Expect.equals(null, e.message);
-  }
-
-  // Test expression can throw.
-  try {
-    assert(throw "test", throw "message");
-  } on String catch (e) {
-    Expect.equals("test", e);
-  }
-
-  // Message expression can throw.
-  try {
-    assert(false, throw "message");
-  } on String catch (e) {
-    Expect.equals("message", e);
-  }
-
-  // Failing asserts evaluate message after test.
-  var list = [];
-  try {
-    assert((list..add(1)).isEmpty, (list..add(3)).length);
-  } on AssertionError catch (e) {
-    Expect.equals(2, e.message);
-    Expect.listEquals([1, 3], list);
-  }
-
-  asyncStart();
-  asyncTests().then((_) {
-    asyncEnd();
-  });
-}
-
-Future asyncTests() async {
-  // You can await in both condition and message.
-  assert(true, await 0);
-  assert(await true, 1);
-  assert(await true, await 2);
-
-  // Successful asserts won't await/evaluate message.
-  void unreachable() => throw "unreachable";
-  assert(await true, await unreachable());
-
-  try {
-    assert(false, await 3);
-  } on AssertionError catch (e) {
-    Expect.equals(3, e.message);
-  }
-
-  var falseFuture = new Future.value(false);
-  var numFuture = new Future.value(4);
-
-  try {
-    assert(await falseFuture, await numFuture);
-  } on AssertionError catch (e) {
-    Expect.equals(4, e.message);
-  }
-
-  try {
-    assert(await falseFuture, await new Future.error("error"));
-  } on String catch (e) {
-    Expect.equals("error", e);
-  }
-}