
Closes https://github.com/flutter/flutter/issues/162703. I still need to do a similar change for `ios|macos`-`framework` in https://github.com/flutter/flutter/issues/162704. I added two unit tests, as well as opted in an integration test to the flag (it will become the default in https://github.com/flutter/flutter/pull/160289). /cc @reidbaker @gmackall.