Previously, one single retained maps list was used across all contexts. When one context was disposed, this entire list of retained maps was disposed as well. This caused maps that were still alive to be disposed leading to deopts when such maps were embedded in code objects.

This patch makes the list of retained maps be per context so we can dispose only the dead maps.

Bug: v8:9684, v8:10431
Change-Id: I0a50f4f49c9f6d72367c62e950828a039220fdfc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2122016Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Sathya Gunasekaran  <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67225}