UnitTests.Diagnostics.ReminderEventsTests.ReminderDiagnosticObserver_WaitsForTickCondition_UntilConditionIsSatisfied intermittently times out in the macOS net8.0 BVT job on current main.

Observed failures:

• https://github.com/dotnet/orleans/actions/runs/32286635266/job/96177621545
• https://github.com/dotnet/orleans/actions/runs/32284315762/job/96170166324

Failure:

System.TimeoutException: The operation has timed out.
at UnitTests.Diagnostics.ReminderEventsTests.ReminderDiagnosticObserver_WaitsForTickCondition_UntilConditionIsSatisfied()
   in test/Orleans.Reminders.Tests/Diagnostics/ReminderEventsTests.cs:line 121

Both failures occurred on unrelated changes, and the latest main run passed, indicating intermittent test behavior. The wait should use a deterministic phase barrier or a condition-specific diagnostic signal rather than depending on timing.