63536 [flutter_tools] move to fake_async, skip failing tests (cla: yes, team, tool, waiting for tree to go green)

63540 [flutter_tools] check for permission issues when copying file (cla: yes, tool, waiting for tree to go green)

63591 1.20.2 Cherrypicks (a: internationalization, cla: yes, engine, f: material design, framework, team, tool, work in progress; do not review)

63605 remove fuchsia_entrypoint_shim directory (cla: yes, team, tool, waiting for tree to go green)

63610 [flutter_tools] support code size tooling on iOS, linux, windows, macOS, and Android on Windows (cla: yes, tool)

63612 [windows] Propagate startup errors in template (cla: yes, tool, waiting for tree to go green)