This change tags pointers in the external pointer table with a type
dependent value in order to prevent type confusions between different
external pointers.

Bug: v8:10391
Change-Id: I5a83178e5ac46d49a99c91047816926120d801d3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2443133Reviewed-by: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Samuel Groß <saelo@google.com>
Cr-Commit-Position: refs/heads/master@{#70430}