Cached template objects only need to be cached for reference identity
comparisons. If there is no strong reference to the cached template
object, then there's nothing to compare it against if it were to be
loaded from the cache, so we can hold it in the cache weakly.

Bug: v8:13190
Change-Id: I4a787eb33eab734fe9df6c424ff915d775fce70f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3898692
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#83220}