The deprecated legacy FinalizationGroup APIs are left unchanged for
compat.

Bug: v8:8179
Change-Id: I9bdcaa92360db318c96fc8524c04163ece25118e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2071236
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66437}