Check response code, retry when downloading docs (#26386)
Check response code, retry when downloading docs (#26386)

When downloading the ObjC/Java API docs, check the HTTP response status
code and if not 200, attempt up to 5 times before giving up.
flutter/flutter,Hixie/flutter,cbracken/flutter,cbracken/flutter,cbracken/flutter,tvolkert/flutter,flutter/flutter,cbracken/flutter,tvolkert/flutter,Hixie/flutter,Hixie/flutter,cbracken/flutter,Hixie/flutter,flutter/flutter,tvolkert/flutter,Hixie/flutter,flutter/flutter,flutter/flutter,Hixie/flutter,Hixie/flutter,cbracken/flutter,Hixie/flutter,Hixie/flutter,tvolkert/flutter,cbracken/flutter,tvolkert/flutter,tvolkert/flutter,flutter/flutter,cbracken/flutter,tvolkert/flutter,tvolkert/flutter,cbracken/flutter,tvolkert/flutter,flutter/flutter,cbracken/flutter,Hixie/flutter,flutter/flutter,flutter/flutter,tvolkert/flutter,flutter/flutter