Set ARCHS to single-arch for local engine macOS builds by @jmagman in https://github.com/flutter/flutter/pull/100917

[flutter_tool] Have long-running validators fail by @christopherfujino in https://github.com/flutter/flutter/pull/100936

[flutter_conductor] Extend timeout for codesign integration test by @christopherfujino in https://github.com/flutter/flutter/pull/100940

Migrate .packages -> package_config.json by @sigurdm in https://github.com/flutter/flutter/pull/99677

Reland “Enable caching of CPU samples collected at application startup (#89600)” by @bkonyi in https://github.com/flutter/flutter/pull/100995