Revert "Suppress canonicalization of Unbox() instruction that can deoptimize."

tests/language/vm/canonicalization_preserves_deopt_test.dart

Index: tests/language/vm/canonicalization_preserves_deopt_test.dart
diff --git a/tests/language/vm/canonicalization_preserves_deopt_test.dart b/tests/language/vm/canonicalization_preserves_deopt_test.dart
deleted file mode 100644
index b36e0eab71588150e5f4e8c284297016633b3513..0000000000000000000000000000000000000000
--- a/tests/language/vm/canonicalization_preserves_deopt_test.dart
+++ /dev/null
@@ -1,20 +0,0 @@
-// Copyright (c) 2014, 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.
-// VMOptions=--optimization_counter_threshold=10 --no-use-osr
-
-import "package:expect/expect.dart";
-
-class X {
-  operator * (other) => "NaNNaNNaNNaNBatman";
-}
-
-foo(x) => (x * 1.0) is double;
-
-main() {
-  for (var i = 0; i < 100; i++) {
-    Expect.isTrue(foo(1.0));
-  }
-  Expect.isFalse(foo(new X()));
-}
-