[Impeller] Start and end a frame in the RenderTargetCache for each rendering of an entity in the playgrounds#49576

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

jason-simmons:iplr_entity_playground_texture_cachejason-simmons/flutter_engine:iplr_entity_playground_texture_cacheCopy head branch name to clipboard