[builtins] HasOwnProperty: handle non-internalized string keys

src/assembler.h

Index: src/assembler.h
diff --git a/src/assembler.h b/src/assembler.h
index dd476d95c4846049a154e16722d2668b05b219d9..57bd68e01e84a5cbae489bfb3cd69546a70e89ee 100644
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -992,6 +992,8 @@ class ExternalReference BASE_EMBEDDED {
   static ExternalReference libc_memcpy_function(Isolate* isolate);
   static ExternalReference libc_memset_function(Isolate* isolate);
 
+  static ExternalReference try_internalize_string_function(Isolate* isolate);
+
   static ExternalReference page_flags(Page* page);
 
   static ExternalReference ForDeoptEntry(Address entry);