ci/turnip: Increase the hangcheck timer to 2 seconds.

We get a lot of useful coverage from running graphicsfuzz with spilling enabled, but it's also pretty slow and can cause intermittent hangcheck failures. I thought I'd categorized them when merging !14839 (merged) (device loss on reset), but it looks like not all of them and we're now more likely to have flakes take out the whole test run when a single flake makes the rest of the caselist a flake.

This is a little unfortunate in that it means our test environment is not the same as a stock system you would want to run deqp on to submit conformance, but I think it's an improvement in the test maintenance work vs needing to fix things up later.

We have some other tests besides turnip that can trigger hangchecks which we might also like this increase for (some disabled traces, for example). However, freedreno GL has a 5-second timeout waiting for idle when mapping, and a couple of 2-second timeouts in a row can result in spurious failures in other tests!

Fixes: #6163 (closed)