[Impeller] Destroy all per-thread command pools tied to a context before deleting the context#46286

auto-submit[bot] merged 1 commit intoflutter:mainflutter/engine:mainfrom

jason-simmons:iplr_thread_cmd_pool_global_mapjason-simmons/flutter_engine:iplr_thread_cmd_pool_global_mapCopy head branch name to clipboard