[Interpreter] Localize the CanonicalHandleScope to parsing and renumbering.

src/ast/ast-value-factory.cc

Index: src/ast/ast-value-factory.cc
diff --git a/src/ast/ast-value-factory.cc b/src/ast/ast-value-factory.cc
index d110bacecd1c59301948b7b5e939882b007b7537..b4fc3dc5a4e86833b312b0b9edb6adf997409afd 100644
--- a/src/ast/ast-value-factory.cc
+++ b/src/ast/ast-value-factory.cc
@@ -262,6 +262,12 @@ const AstConsString* AstValueFactory::NewConsString(
 
 
 void AstValueFactory::Internalize(Isolate* isolate) {
+  // Create a canonical handle scope if compiling ignition bytecode. This is
+  // required by the constant array builder to de-duplicate objects without
+  // dereferencing handles.
+  std::unique_ptr<CanonicalHandleScope> canonical;
+  if (FLAG_ignition) canonical.reset(new CanonicalHandleScope(isolate));
+
   // Strings need to be internalized before values, because values refer to
   // strings.
   for (AstString* current = strings_; current != nullptr;) {