Add ticking behavior tests

These tests cover the behavior of the WallClockTimer when it is ticking,
including how it handles wall clock and monotonic clock synchronization,
drift, and jumps. The tests include scenarios where the clocks are in sync,
where there is a constant drift (both forward and backward), and where there
are jumps in the wall clock time. The tests also verify that the timer
adjusts its sleep time accordingly and that it logs appropriate warnings
when the wall clock time drifts too much from the monotonic time.

These tests cover for the most common cases, but are not comprehensive.
With the current test infrastructure, it should be possible to add tests
for more scenarios fairly easily in the future as needed.

Signed-off-by: Leandro Lucarella <[email protected]>

Author: llucax