dominoes 1.0.1: correctly declare nine elements in largest case (#777)
dominoes 1.0.1: correctly declare nine elements in largest case (#777)

There have always been nine elements, ever since the origin of this test
in https://github.com/exercism/xrust/pull/13#discussion_r115148635

The description incorrectly claimed ten.
rpottsoh/x-common,Vankog/problem-specifications,exercism/x-common,kgengler/x-common,kgengler/x-common,jmluy/x-common,ErikSchierboom/x-common,petertseng/x-common,ErikSchierboom/x-common,petertseng/x-common,rpottsoh/x-common,exercism/x-common,Vankog/problem-specifications,jmluy/x-common,jmluy/x-common