More dart 2 fixes to fuchsia_tester.dart (#19846)
More dart 2 fixes to fuchsia_tester.dart (#19846)


cbracken/flutter,cbracken/flutter,tvolkert/flutter,cbracken/flutter,flutter/flutter,cbracken/flutter,tvolkert/flutter,Hixie/flutter,tvolkert/flutter,cbracken/flutter,cbracken/flutter,Hixie/flutter,flutter/flutter,flutter/flutter,tvolkert/flutter,cbracken/flutter,cbracken/flutter,Hixie/flutter,Hixie/flutter,flutter/flutter,Hixie/flutter,flutter/flutter,Hixie/flutter,tvolkert/flutter,tvolkert/flutter,Hixie/flutter,tvolkert/flutter,Hixie/flutter,flutter/flutter,flutter/flutter,tvolkert/flutter,flutter/flutter,Hixie/flutter,flutter/flutter,Hixie/flutter,cbracken/flutter,cbracken/flutter,tvolkert/flutter,tvolkert/flutter,flutter/flutter