Reintroduce S14-roles/generic-subtyping.t

[Kaiepi]

Now a more exhaustive test of various edge cases in role typechecking exposed this way.

Depends on https://github.com/rakudo/rakudo/pull/4478 to pass.

[vrurg]

Wouldn't it be better to fudge those non-compiling tests for the time being? The skip fudge verb is exactly the one for the job. When your fix is complete, there will be no need in EVALs anyway. But their removal will tremendously improve test readability.