Add support for per-isolate private symbols

src/macros.py

Index: src/macros.py
diff --git a/src/macros.py b/src/macros.py
index 1722c6c7de2151168469053d4215c31ae3bdd2b8..0b69e6b80e436d477d8a94867d07071bd221101a 100644
--- a/src/macros.py
+++ b/src/macros.py
@@ -162,6 +162,7 @@ macro TO_OBJECT_INLINE(arg) = (IS_SPEC_OBJECT(%IS_VAR(arg)) ? arg : ToObject(arg
 macro JSON_NUMBER_TO_STRING(arg) = ((%_IsSmi(%IS_VAR(arg)) || arg - arg == 0) ? %_NumberToString(arg) : "null");
 
 # Private names.
+macro GLOBAL_PRIVATE(name) = (%CreateGlobalPrivateSymbol(name));
 macro NEW_PRIVATE(name) = (%CreatePrivateSymbol(name));
 macro IS_PRIVATE(sym) = (%SymbolIsPrivate(sym));
 macro HAS_PRIVATE(obj, sym) = (sym in obj);