- Explain the reason on why the test fails if it fails
- Relax offset for ZTIMER_USEC on native, as this depends on the jitter
emitted by the non-realtime OS native is running on
fixes issue #18490
The callback function of `ztimer_periodic` is only expected to have
two states.
So let it return `true` if the timer should keep repeating, `false`
otherwise.
The macro with name `N` is used by the MSP430 CPU macros and
triggers a compilation error if this example is build for that
platform. So this commit renames the repeat counter limit from
`N` to `REAPEAT`.
Instead of only testing for `ZTIMER_MSEC`, iterate over a list of
clocks and run the test for each. The reasoning is that this test
does not only test `ztimer_periodic`, but also that the used clock
backend operates correctly in a typical use case.
