39628 Automatically generated registrants for web plugins (cla: yes, team, tool, ☸ platform-web)

39632 Updates to debugFillProperties to test all properties in slider.dart and slider_test.dart (cla: yes, f: material design, framework, waiting for tree to go green)

39654 Use persisted build information to automatically clean old outputs (cla: yes, tool)

39670 Center action icons of swipe to dismiss example (cla: yes, d: examples, f: material design, team, team: gallery)

39699 Detecting when installing over MingW’s Git Bash, fixing paths (cla: yes, tool, waiting for tree to go green)

39701 Remove input files argument to target (cla: yes, tool)

39702 Fix macOS App.framework version symlink (cla: yes, tool)