Fix a LICM bug where we were loop hoisting an isntruction, even though that isntruction's inputs we…

tests/language/licm_test.dart

+// Copyright (c) 2012, 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.
+
+var sum = 0;
+var foo = 0;
+var bar = 1;
+
+test() {
+  while (true) {
+    if (0 === foo) {
+      sum += 2;
+      if (1 === bar) {
+        sum += 3;
+        break;
+      }
+      break;
+    }
+  }
+}
+
+main() {
+  test();
+  Expect.equals(5, sum);
+}