Only commitRunningAppsToUI if shownTasks changed

- Add GroupTask and DesktopTask equals() (with tests)
- Add tests to verify multiple onRecentTasksChanged
  doesn't commitRunningAppsToUI if there's no change
- Add tests to verify commitRunningAppsToUI is still
  called if minimized or running apps set changes

Bug: 348802109
Bug: 348787176
Test: TaskbarRecentAppsControllerTest
Test: GroupTaskTest
Test: log TaskbarView#onMeasure() locally, ensure it is called
much less despite noisy onRecentTasksChanged callbacks
Flag: com.android.window.flags.enable_desktop_windowing_taskbar_running_apps

Change-Id: I3efff7f4492272f88aa2bdbd7cc45bd2bf8156f6