Use NumberIsNaN in collections.js and make it inlined

src/collection.js

 // Copyright 2012 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.
 
 "use strict";
 
 // This file relies on the fact that the following declaration has been made
 // in runtime.js:
 // var $Array = global.Array;
 
 var $Set = global.Set;
 var $Map = global.Map;
 
 
 (function() {
 
 %CheckIsBootstrapping();
 
 
 function HashToEntry(table, hash, numBuckets) {
   var bucket = ORDERED_HASH_TABLE_HASH_TO_BUCKET(hash, numBuckets);
   return ORDERED_HASH_TABLE_BUCKET_AT(table, bucket);
 }
 %SetInlineBuiltinFlag(HashToEntry);
 
 
 function SetFindEntry(table, numBuckets, key, hash) {
-  var keyIsNaN = IS_NUMBER(key) && NUMBER_IS_NAN(key);
+  var keyIsNaN = NumberIsNaN(key);
   for (var entry = HashToEntry(table, hash, numBuckets);
        entry !== NOT_FOUND;
        entry = ORDERED_HASH_SET_CHAIN_AT(table, entry, numBuckets)) {
     var candidate = ORDERED_HASH_SET_KEY_AT(table, entry, numBuckets);
     if (key === candidate) {
       return entry;
     }
-    if (keyIsNaN && IS_NUMBER(candidate) && NUMBER_IS_NAN(candidate)) {
+    if (keyIsNaN && NumberIsNaN(candidate)) {
       return entry;
     }
   }
   return NOT_FOUND;
 }
 %SetInlineBuiltinFlag(SetFindEntry);
 
 
 function MapFindEntry(table, numBuckets, key, hash) {
-  var keyIsNaN = IS_NUMBER(key) && NUMBER_IS_NAN(key);
+  var keyIsNaN = NumberIsNaN(key);
   for (var entry = HashToEntry(table, hash, numBuckets);
        entry !== NOT_FOUND;
        entry = ORDERED_HASH_MAP_CHAIN_AT(table, entry, numBuckets)) {
     var candidate = ORDERED_HASH_MAP_KEY_AT(table, entry, numBuckets);
     if (key === candidate) {
       return entry;
     }
-    if (keyIsNaN && IS_NUMBER(candidate) && NUMBER_IS_NAN(candidate)) {
+    if (keyIsNaN && NumberIsNaN(candidate)) {
       return entry;
     }
   }
   return NOT_FOUND;
 }
 %SetInlineBuiltinFlag(MapFindEntry);
 
 
 function ComputeIntegerHash(key, seed) {
   var hash = key;
@@ skipping 371 matching lines @@
 InstallFunctions($Map.prototype, DONT_ENUM, $Array(
   "get", MapGet,
   "set", MapSet,
   "has", MapHas,
   "delete", MapDelete,
   "clear", MapClearJS,
   "forEach", MapForEach
 ));
 
 })();