[test] Port GPUDirect check to Tiger

[jgphpc]

Will fix UES-580

Changes needed to run on tiger, is there a better way to do it ?

[vkarak]

@jgphpc To answer your question "is there a better way to do it ?"

I don't think you can do it differently for the moment, but in the future we can think of attaching attributes to systems, that we can later check in the tests. That would decouple the test further.

[jgphpc]

#966 (comment)

Would it be possible to detect that we are on a Cray system (/opt/cray/ or /etc/opt/cray/release exist) then we could use stg like:
if self.current_system.name in {'dom', 'daint', CRAY}:
instead of
if self.current_system.name in {'dom', 'daint', 'tiger'}:
?

or stg like: reframe --skip-system-check --cray-system