[turbofan] Don't treat the hole NaN as constant inside the compiler.

test/mjsunit/regress/regress-5332.js

+// Copyright 2016 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.
+
+// Flags: --allow-natives-syntax
+
+(function() {
+  function foo() {
+    var a = new Array(2);
+    a[1] = 1.5;
+    return a;
+  }
+
+  assertEquals(undefined, foo()[0]);
+  assertEquals(undefined, foo()[0]);
+  %OptimizeFunctionOnNextCall(foo);
+  assertEquals(undefined, foo()[0]);
+})();
+
+(function() {
+  function foo() {
+    var a = Array(2);
+    a[1] = 1.5;
+    return a;
+  }
+
+  assertEquals(undefined, foo()[0]);
+  assertEquals(undefined, foo()[0]);
+  %OptimizeFunctionOnNextCall(foo);
+  assertEquals(undefined, foo()[0]);
+})();