Prior to this CL we regularly generated high counts of code
dependencies, and installation was not the most efficient.

This CL 1) implements early dependency deduplication and
2) simplifies the way dependencies are persisted on the heap
through DependentCode.

Re 1): we dedupe twice, once based on the CompilationDependency
contents, and again once we know the final target object.

Re 2): Instead of a linked list of weak fixed arrays per
dependency group, store deps in a flat array together with a
bitset of their dependency groups.

See also:
https://docs.google.com/document/d/1B34S1s3Iv6hbquZ93RugD0b-ZKfHEptJ8Fk_YyOvjDk/edit

Bug: v8:12195,v8:12397
Change-Id: I9ab47f6d87b10558194b5de30a36b1122f7e362a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3283074Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77969}