Tests in timer/timer_impl.rs are time sensitive and can be flaky

[vmingchen]

These tests cover the Timer API, so they are sensitive to timing and can be flaky if the dev environment changes. We need to make them more robust.

[glommer]

Fully Agree.

Usually the way to make it work is to have a parametrized clock implementation that defaults to wallclock, but for tests you can pass your own that you can manually control.