Improve ValueSerializer perf regression after 96635558

src/value-serializer.cc

Index: src/value-serializer.cc
diff --git a/src/value-serializer.cc b/src/value-serializer.cc
index 51fdf2212b4f2a5420fd22b7f98a9a8d4e7401cc..faf44759ba93612cbd2adeb40a3e3eeacd566839 100644
--- a/src/value-serializer.cc
+++ b/src/value-serializer.cc
@@ -232,7 +232,7 @@ void ValueSerializer::WriteRawBytes(const void* source, size_t length) {
 Maybe<uint8_t*> ValueSerializer::ReserveRawBytes(size_t bytes) {
   size_t old_size = buffer_size_;
   size_t new_size = old_size + bytes;
-  if (new_size > buffer_capacity_) {
+  if (V8_UNLIKELY(new_size > buffer_capacity_)) {
     bool ok;
     if (!ExpandBuffer(new_size).To(&ok)) {
       return Nothing<uint8_t*>();