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

src/harmony-regexp.js

Index: src/harmony-regexp.js
diff --git a/src/harmony-regexp.js b/src/harmony-regexp.js
index f4e1cb0f3fa109d7ecc5420c0c0fc247a7feda81..150716744da8f3ad76d90a248e99bf09bd7989ae 100644
--- a/src/harmony-regexp.js
+++ b/src/harmony-regexp.js
@@ -8,7 +8,15 @@
 
 %CheckIsBootstrapping();
 
+// -------------------------------------------------------------------
+// Imports
+
 var GlobalRegExp = global.RegExp;
+var ToString;
+
+utils.Import(function(from) {
+  ToString = from.ToString;
+});
 
 // -------------------------------------------------------------------
 
@@ -16,7 +24,7 @@ var GlobalRegExp = global.RegExp;
 // + https://bugs.ecmascript.org/show_bug.cgi?id=3423
 function RegExpGetFlags() {
   if (!IS_SPEC_OBJECT(this)) {
-    throw MakeTypeError(kFlagsGetterNonObject, $toString(this));
+    throw MakeTypeError(kFlagsGetterNonObject, ToString(this));
   }
   var result = '';
   if (this.global) result += 'g';