Fix https://code.google.com/p/dart/issues/detail?id=10474 by not loop hoisting instructions that ma…

tests/language/licm2_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.
+
+// Test that a loop invariant code motion optimization does not try to
+// hoist instructions that may throw.
+
+import "package:expect/expect.dart";
+
+var a = 42;
+var b;
+
+main() {
+  Expect.throws(() {
+    while (true) {
+      a = 54;
+      b.length;
+    }
+  });
+  b = [];
+  Expect.equals(54, a);
+}