Fix bug in tests.benchmark.test_utils

Too slow ScenarioTestCase.test_run_scenario_timeout
was fixed by correct settings of 'too_long' method in
FakeScenario and default timeout values in the test,
which led to an increase in the speed of this test.

Change-Id: I5748108e14ddd7639fc792dca2df9fc8829f32f8
Closes-Bug: #1242230
Merge "Fix bug in tests.benchmark.test_utils"