Fix bug in the requested type of an SSA instruction: avoid requesting a ContainerTypeMask.

tests/language/bailout_container_type_test.dart

Index: tests/language/bailout_container_type_test.dart
===================================================================
--- tests/language/bailout_container_type_test.dart	(revision 0)
+++ tests/language/bailout_container_type_test.dart	(revision 0)
@@ -0,0 +1,27 @@
+// 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.
+
+// Regression test for dart2js that used to generate bad code for the
+// non-bailout version of [main].
+
+var a = [false, [1, 2, 3]];
+var b;
+
+main() {
+  // Defeat type inferencing for [b].
+  b = new Object();
+  b = 42;
+  b = [];
+
+  // Make the function recursive to force a bailout version.
+  if (a[0]) main();
+
+  // We used to ask [b] to be of the same type as [a], but not
+  // checking that the length and element type are the same.
+  var arrayPhi = a[0] ? a : b;
+
+  if (arrayPhi.length != 0) {
+    throw 'Test failed';
+  }
+}