[Piglit] Revert test Timeouts

[Dylan Baker]

This series reverts test timeouts introduced for igt tests.

We actually really want timeouts, but this implementation introduces
problems when running concurrently; namely that the locking for the json
file stops working and json becomes corrupted in a completely unrepairable
way. I have tried several times to fix this and have simply come to the
conclusion that it isn't possible to fix it, and that to avoid further
headache it's best to revert it.