[turbofan] Only replace nodes eagerly during simplified lowering if the types stay the same.

test/mjsunit/compiler/regress-452427.js

Index: test/mjsunit/compiler/regress-452427.js
diff --git a/test/mjsunit/compiler/regress-452427.js b/test/mjsunit/compiler/regress-452427.js
new file mode 100644
index 0000000000000000000000000000000000000000..f798b9cc79cafc85ae906df1cdb48debaa96b6d0
--- /dev/null
+++ b/test/mjsunit/compiler/regress-452427.js
@@ -0,0 +1,18 @@
+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+var stdlib = {};
+var foreign = {};
+var heap = new ArrayBuffer(64 * 1024);
+
+var rol = (function Module(stdlib, foreign, heap) {
+  "use asm";
+  function rol() {
+    y = "a" > false;
+    return y + (1 - y);
+  }
+  return { rol: rol };
+})(stdlib, foreign, heap).rol;
+
+assertEquals(1, rol());