Clean up some tests in module test_role_v2

The only non-stubbed tests that use the old API tools are in module
`test_permission`. Those tests interact heavily with the `/roles` API URL, and
they will likely be ported to module `test_role_v2`. In preparation for this,
clean up module `test_role_v2`.
Merge pull request #1488 from Ichimonji10/test-role

Clean up some tests in module test_role_v2