[PATCH v2 0/3] MR10095: mf: Implement IMFTimer using a periodic callback.

[Brendan McGrath (＠redmcg)]

In preparation for adding the `IMFPresentationTimeSource` interface to SAR, this MR adds tests for `IMFPresentationClock` using a custom `IMFPresentationTimeSource`.

These tests highlighted a couple of issues in wine:
1. Clock events are sent to a clock sink twice if it is also the presentation time source; and
2. The `IMFTimer::SetTimer` calls do not work correctly.

This MR also addresses both of these issues.

--
  v2: mf: Implement IMFTimer using a periodic callback.
      mf: Don't async notify a sink that is also the time source.
      mf/tests: Test presentation clock with custom time source.
 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10095