[CI] ensure py.test is ran on runner with rapl

Since our tests include checking that coolr can access the rapl
interface, we should ensure that only runners having rapl will test the
code.
3 jobs for ci-tags in 3 minutes and 45 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
passed #11861
rapl
py.test

00:02:36

failed #11859
rapl
py.test

00:00:03

 
  Style
passed #11860
flake8

00:01:08