buffer: fix assertion error in WeakCallback
CallbackInfo
is now bound to ArrayBuffer
instance, not Uint8Array
,
therefore SPREAD_ARG
will abort with:
Assertion failed: ((object)->IsUint8Array())
Make changes necessary to migrate it to ArrayBuffer
.
See: https://github.com/nodejs/node/pull/3080#issuecomment-147502167
R=@trevnorris