Revert two Kernel changes that were causing test failures.

tests/language_2/assert_assignable_type_test.dart

Index: tests/language_2/assert_assignable_type_test.dart
diff --git a/tests/language_2/assert_assignable_type_test.dart b/tests/language_2/assert_assignable_type_test.dart
deleted file mode 100644
index 9721bf244c4f5a72a2e09940ee4a1abd6594676c..0000000000000000000000000000000000000000
--- a/tests/language_2/assert_assignable_type_test.dart
+++ /dev/null
@@ -1,28 +0,0 @@
-// Copyright (c) 2013, 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.
-// Dart test program to test arithmetic operations.
-// VMOptions=--optimization-counter-threshold=10 --checked --no-background-compilation
-
-// This test crashes if we recompute type of AssertAssignableInstr based on its
-// output types. By doing that we would eliminate not only the unnecessary
-// AssertAssignableInstr but also the trailing class check.
-
-main() {
-  // Foul up  IC data in integer's unary minus.
-  var y = -0x80000000;
-  testInt64List();
-}
-
-testInt64List() {
-  var array = new List(10);
-  testInt64ListImpl(array);
-}
-
-testInt64ListImpl(array) {
-  for (int i = 0; i < 10; ++i) {}
-  int sum = 0;
-  for (int i = 0; i < 10; ++i) {
-    array[i] = -0x80000000000000 + i;
-  }
-}