Fix bug http://code.google.com/p/dart/issues/detail?id=12941 by doing speculative optimizations eve…

tests/compiler/dart2js/bailout_indexable_test.dart

+// 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.
+
+import "package:expect/expect.dart";
+import 'compiler_helper.dart';
+
+const String TEST = '''
+foo(a) {
+  foo([]);
+  print(a[0]);
+}
+''';
+
+main() {
+  String generated = compile(
+      TEST,
+      entry: 'foo',
+      interceptorsSource: DEFAULT_INTERCEPTORSLIB
+      // ADD a bogus indexable class that does not have [].
+          + 'class BogusIndexable implements JSIndexable {}');
+
+  // Ensure that we still generate an optimized version, even if there
+  // is an indexable class that does not implement [].
+  Expect.isTrue(!generated.contains('index'));
+}