Double field values need sNaN -> qNaN canonicalization.

test/mjsunit/regress/regress-undefined-nan3.js

 // 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.
 
 // Flags: --allow-natives-syntax
 
-function loader(dst, src, i) {
-  dst[i] = src[i];
-}
-
 var ab = new ArrayBuffer(8);
 var i_view = new Int32Array(ab);
 i_view[0] = 0xFFF7FFFF;
 i_view[1] = 0xFFF7FFFF;
 var f_view = new Float64Array(ab);
 
 var fixed_double_elements = new Float64Array(1);
 fixed_double_elements[0] = f_view[0];
 
+function A(src) { this.x = src[0]; }
+
+new A(fixed_double_elements);
+new A(fixed_double_elements);
+
+%OptimizeFunctionOnNextCall(A);
+
+var obj = new A(fixed_double_elements);
+
+function move_x(dst, obj) { dst[0] = obj.x; }
+
 var doubles = [0.5];
-loader(doubles, fixed_double_elements, 0);
-loader(doubles, fixed_double_elements, 0);
-%OptimizeFunctionOnNextCall(loader);
-loader(doubles, fixed_double_elements, 0);
+move_x(doubles, obj);
+move_x(doubles, obj);
+%OptimizeFunctionOnNextCall(move_x);
+move_x(doubles, obj);
 assertTrue(doubles[0] !== undefined);