Remove unused method in RouteSet test.
Merge pull request #15116 from tgxworld/remove_unused_method_in_test

Remove unused method in RouteSet test.
Remove ruby-head from allow_failures matrix
Revert "Remove ruby-head from allow_failures matrix"

This reverts commit 5d2d301024cc0b17f26f6b454ac22a72f1db8a23.