Add null check to _IndicatorPainter._tabOffsetsEqual() to prevent crash (#40009)
Add null check to _IndicatorPainter._tabOffsetsEqual() to prevent crash (#40009)

* Add tabOffsetEqual null check with TODO
flutter/flutter,flutter/flutter,cbracken/flutter,flutter/flutter,tvolkert/flutter,cbracken/flutter,flutter/flutter,tvolkert/flutter,cbracken/flutter,flutter/flutter,tvolkert/flutter,flutter/flutter,flutter/flutter,tvolkert/flutter,tvolkert/flutter,cbracken/flutter,flutter/flutter,tvolkert/flutter,flutter/flutter,tvolkert/flutter,Hixie/flutter,Hixie/flutter,cbracken/flutter,cbracken/flutter,tvolkert/flutter,tvolkert/flutter,flutter/flutter,cbracken/flutter,tvolkert/flutter,Hixie/flutter,Hixie/flutter,Hixie/flutter,cbracken/flutter,cbracken/flutter,Hixie/flutter,Hixie/flutter,Hixie/flutter,cbracken/flutter,Hixie/flutter,Hixie/flutter