Fix TimeProvider Test (#111080)

Author: tarekgh

src/libraries/Common/tests/System/TimeProviderTests.cs

@@ -143,7 +143,9 @@ public void TestProviderTimer(TimeProvider provider, int minMilliseconds)
             state.TokenSource.Token.WaitHandle.WaitOne(Timeout.InfiniteTimeSpan);
             state.TokenSource.Dispose();
 
-            Assert.Equal(4, state.Counter);
+            // In normal conditions, the timer callback should be called 4 times. Sometimes the timer callback could be queued and fired after the timer was disposed.
+            Assert.True(state.Counter >= 4, $"The timer callback was expected to be called at least 4 times, but was called {state.Counter} times");
+
             Assert.Equal(400, state.Period);
             Assert.True(minMilliseconds <= state.Stopwatch.ElapsedMilliseconds, $"The total fired periods {state.Stopwatch.ElapsedMilliseconds}ms expected to be greater then the expected min {minMilliseconds}ms");
         }