The GC already treats some embedded object pointers in Code as weak,
based on Code::IsWeakObject. If one of those embedded objects ends up
unmarked during a full mark-collect GC, then the Code is marked for lazy
deoptimization and the embedded objects are cleared. However, many of
those same objects are often held strongly by the deoptimization literal
array for the Code, which causes memory leaks. This change updates the
deoptimization literals array to store those objects weakly. Any Code
currently executing on the stack might need those deoptimization
literals in order to deoptimize, so the deoptimization literal array is
marked strongly in that case.

Design document:
https://docs.google.com/document/d/1gFRBYCeqz9Mysx8CVYQkldBbk3AZLo8UX0DMLZV_7qw/edit?usp=sharing

Bug: v8:4578
Change-Id: I02e86683c59371e9f88ecf523750c9c6afebdb39
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3160299Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#77805}