Unify symbols sharing across native scripts and runtime.

src/collection.js

Index: src/collection.js
diff --git a/src/collection.js b/src/collection.js
index 6d43384e1cecf440de2abc3067cab0a51528ae9c..07d7c5c61b99c4256e2321fdaeb3ad570713fac5 100644
--- a/src/collection.js
+++ b/src/collection.js
@@ -16,6 +16,7 @@ var $getExistingHash;
 var GlobalMap = global.Map;
 var GlobalObject = global.Object;
 var GlobalSet = global.Set;
+var hashCodeSymbol = utils.GetPrivateSymbol("hash_code_symbol");
 var IntRandom;
 
 utils.Import(function(from) {
@@ -90,8 +91,6 @@ function ComputeIntegerHash(key, seed) {
 }
 %SetForceInlineFlag(ComputeIntegerHash);
 
-var hashCodeSymbol = GLOBAL_PRIVATE("hash_code_symbol");
-
 function GetExistingHash(key) {
   if (%_IsSmi(key)) {
     return ComputeIntegerHash(key, 0);