[test] Fix test-api.cc test for caching of FunctionTemplate.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index dc51f3a2330ddbf059384be3fb2ba6ea9ec3bae7..1aafd0b709f0856879a529a74102bf435705e40a 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -1276,7 +1276,7 @@ static Local<FunctionTemplate> FunctionTemplateNew(
       i::Handle<i::FunctionTemplateInfo>::cast(struct_obj);
   InitializeFunctionTemplate(obj);
   obj->set_do_not_cache(do_not_cache);
-  int next_serial_number = 0;
+  int next_serial_number = i::FunctionTemplateInfo::kInvalidSerialNumber;
   if (!do_not_cache) {
     next_serial_number = isolate->heap()->GetNextTemplateSerialNumber();
   }