Flaky fails in this test suggest that the VM on which the
test is executed does not get CPU resources allocated for enough time
to make this test pass. This change makes the test more resilient by
taking the measurements as quickly as possible.
In addition, use a sanity-check based on std::chrono APIs to abort the
test completely if we see that the clock has advanced too far to make
the following tests meaningful.
Change-Id: Ie6ac4ffb52f20e7774014f8222c9cd8f54d8a263
Fixes: QTBUG-64517
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
8b9a025373