Bug 16044: Make tests from t/Cache.t pass

 Bug 16044: Make tests from t/Cache.t pass

The timeout does not impact the L1 cache (it would be to time consuming
and not really useful to do that for this cache).
To simulate the real timeout, we need to flush this L1 cache when
needed.
It would be also done adding a disable_L1_cache method.

Signed-off-by: Jesse Weaver <jweaver@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Brendan A Gallagher <brendan@bywatersolutions.com>