src: don't assume v8::Local is using-declared

PR-URL: #11464
Reviewed-By: Steven R Loomis <srloomis@us.ibm.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: James M Snell <jasnell@gmail.com>

src/util.h

@@ -394,7 +394,7 @@ class BufferValue : public MaybeStackBuffer<char> {
 
 #define SPREAD_BUFFER_ARG(val, name) \
  CHECK((val)->IsUint8Array()); \
- Local<v8::Uint8Array> name = (val).As<v8::Uint8Array>();  \
+ v8::Local<v8::Uint8Array> name = (val).As<v8::Uint8Array>(); \
  v8::ArrayBuffer::Contents name##_c = name->Buffer()->GetContents(); \
  const size_t name##_offset = name->ByteOffset(); \
  const size_t name##_length = name->ByteLength(); \