Fix load-sensitive tests
Fix a couple of load-sensitive tests that were detected during gitlab runner load testing. For example: https://gitlab.wikimedia.org/repos/releng/scap/-/jobs/81170
tests/scap/test_checks.py: ChecksExecuteTest: test_execute_concurrency: Only compare the order in which jobs started/finished. Don't use absolute duration comparisons. test_execute_timeout: Sleep for a much longer time to allow plenty of time for the timeout to take effect.