zink/ci: increase piglit and deqp-runner timeouts

A bunch of tests are currently taking ~60 seconds, dangerously close to the current 60 seconds timeout. Add some congesion or just bad luck to a runner, or some other background-task, and we can very easily be pushed above that.

Since we're rendering on LLVMpipe rather than HW, this isn't as unreasonable as it might sound at first. So let's copy a trick from VirGL's CI playbook, and bump the timeout to 180 seconds, three times of what we currently use.

That might seem a bit excessive, but it's better to make it very unlikely to cause trouble than a little bit unlikely.