This CL introduces a new root that is conceptually a

WeakMap<ScopeInfo, Tuple2<ScopeInfo, StringSet>>

Instead of storing the "locals block list" for debug-evaluate on the
`ScopeInfo` object directly, we will store it instead in a global
WeakMap. This enables us to re-use the "locals block lists" across
multiple debug-evaluate invocations without having to modify the
`ScopeInfo` of `SharedFunctionInfo`s.

R=bmeurer@chromium.org

Doc: https://bit.ly/chrome-devtools-debug-evaluate-design
Bug: chromium:1363561
Change-Id: Ib52f9abd97cf1c8fa3053ff3c61a6062c4b814be
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3902041Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/main@{#83318}