Narrow down test durations a little

[not-raspberry]

Longest test durations:

10.02s call     test/unit/test_executor.py::test_execute_pre_checks_fail[5]
10.02s call     test/unit/test_executor.py::test_execute_pre_checks_fail[3]
10.02s call     test/unit/test_executor.py::test_execute_pre_checks_fail[4]
10.02s call     test/unit/test_executor.py::test_execute_pre_checks_fail[2]
10.02s call     test/unit/test_executor.py::test_execute_pre_checks_fail[1]
5.17s call     test/integration/test_spawn_and_check.py::test_execute_check_http[5]
5.15s call     test/integration/test_spawn_and_check.py::test_execute_check_tcp[5]
5.11s call     test/integration/test_spawn_and_check.py::test_execute_check_unix[5]
4.09s call     test/integration/test_spawn_and_check.py::test_execute_failing_checks
3.26s call     test/integration/test_spawn_and_check.py::test_execute_same_service_sequentially
3.16s call     test/integration/test_spawn_and_check.py::test_execute_check_tcp[3]
3.15s call     test/integration/test_spawn_and_check.py::test_execute_check_http[3]
3.11s call     test/integration/test_spawn_and_check.py::test_execute_check_unix[3]
1.14s call     test/integration/test_spawn_and_check.py::test_execute_process_killed

Those tests are mostly sleeping. It would be nice to e.g. reduce timeouts for unit tests.

Another, more complicated way is to mock time.sleep and time.time.

[not-raspberry]

84.13 down to 34.43.