... for defining isolate-full getters.

Bug: v8:9353
Change-Id: I91aa11bfe41ab61b2fa72c21018fc38753a846bd
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1676286Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62375}