Both PropertyCallbackInfo<T> and WeakCallbackInfo<T> callbacks are
using a design that relies on invalid reinterpret_casts and thereby
undefined behavior. Since they are exposed via the public API, fixing
this is going to be difficult.

Bug: v8:3770,v8:8735
Change-Id: I7171c5b38f070b4a43a0de1ebb7d1a1458c1d91f
Reviewed-on: https://chromium-review.googlesource.com/c/1436222Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59083}