Fix tabs Semantics test (#12620)
Fix tabs Semantics test (#12620)

Merge confliuct between #12605 and #12613
tvolkert/flutter,tvolkert/flutter,flutter/flutter,flutter/flutter,cbracken/flutter,cbracken/flutter,cbracken/flutter,Hixie/flutter,cbracken/flutter,tvolkert/flutter,tvolkert/flutter,tvolkert/flutter,cbracken/flutter,cbracken/flutter,flutter/flutter,cbracken/flutter,tvolkert/flutter,tvolkert/flutter,cbracken/flutter,flutter/flutter,cbracken/flutter,tvolkert/flutter,tvolkert/flutter,Hixie/flutter,Hixie/flutter,flutter/flutter,flutter/flutter,tvolkert/flutter,flutter/flutter,flutter/flutter,Hixie/flutter,flutter/flutter,Hixie/flutter,Hixie/flutter,Hixie/flutter,flutter/flutter,Hixie/flutter,Hixie/flutter,Hixie/flutter,cbracken/flutter