- Avoid lookup if there is no template_weakmap yet
- More explicit DisallowGarbageCollection scopes
- Avoid handles when settings properties
- Speed up Object::GetSimpleHash by loading only instance_type once

Change-Id: Ib588607340a0c56dc1ba26c3e89485560222a688
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3463717Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79189}