Go back to `-j1` in flutter_tools tests (#24196)
Go back to `-j1` in flutter_tools tests (#24196)

To see if it stops the Cirrus crashing
flutter/flutter,cbracken/flutter,cbracken/flutter,tvolkert/flutter,flutter/flutter,cbracken/flutter,Hixie/flutter,tvolkert/flutter,tvolkert/flutter,cbracken/flutter,Hixie/flutter,flutter/flutter,tvolkert/flutter,tvolkert/flutter,Hixie/flutter,cbracken/flutter,tvolkert/flutter,Hixie/flutter,cbracken/flutter,flutter/flutter,flutter/flutter,Hixie/flutter,tvolkert/flutter,Hixie/flutter,flutter/flutter,Hixie/flutter,tvolkert/flutter,flutter/flutter,cbracken/flutter,cbracken/flutter,Hixie/flutter,flutter/flutter,cbracken/flutter,tvolkert/flutter,flutter/flutter,tvolkert/flutter,Hixie/flutter,cbracken/flutter,Hixie/flutter,flutter/flutter