Native context: debug.js does not load from js builtins object anymore.

src/symbol.js

Index: src/symbol.js
diff --git a/src/symbol.js b/src/symbol.js
index 5c5ec007afa5087f003232ab716a6de7de139a41..8cac2c56a2f69cfa8397c6c13bb0d07ef9f33f1f 100644
--- a/src/symbol.js
+++ b/src/symbol.js
@@ -23,11 +23,12 @@ var $symbolToString;
 
 var GlobalObject = global.Object;
 var GlobalSymbol = global.Symbol;
-
 var ObjectGetOwnPropertyKeys;
+var ToString;
 
 utils.Import(function(from) {
   ObjectGetOwnPropertyKeys = from.ObjectGetOwnPropertyKeys;
+  ToString = from.ToString;
 });
 
 // -------------------------------------------------------------------
@@ -35,7 +36,7 @@ utils.Import(function(from) {
 function SymbolConstructor(x) {
   if (%_IsConstructCall()) throw MakeTypeError(kNotConstructor, "Symbol");
   // NOTE: Passing in a Symbol value will throw on ToString().
-  return %CreateSymbol(IS_UNDEFINED(x) ? x : $toString(x));
+  return %CreateSymbol(IS_UNDEFINED(x) ? x : ToString(x));
 }