Fix: copy-paste error in raw ptr GC update function.

Bug: v8:11525
Change-Id: I915ae92191b2add60962395a2d0ad28f57e02fd4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3622915
Commit-Queue: Marja Hölttä <marja@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80328}