Fix timer keeps active when resampling disabled in some cases (#97197)

Author: wangying3426

packages/flutter/lib/src/gestures/binding.dart

@@ -180,6 +180,7 @@ class _Resampler {
     }
     _resamplers.clear();
     _frameTime = Duration.zero;
+    _timer?.cancel();
   }
 
   void _onSampleTimeChanged() {

packages/flutter/test/gestures/gesture_binding_resample_event_on_widget_test.dart

@@ -123,4 +123,20 @@ void main() {
     expect(events[3].timeStamp, currentTestFrameTime() + kSamplingOffset);
     expect(events[3], isA<PointerUpEvent>());
   });
+
+  testWidgets('Timer should be canceled when resampling stopped', (WidgetTester tester) async {
+    // A timer will be started when event's timeStamp is larger than sampleTime.
+    final ui.PointerDataPacket packet = ui.PointerDataPacket(
+      data: <ui.PointerData>[
+        ui.PointerData(
+          timeStamp: Duration(microseconds: DateTime.now().microsecondsSinceEpoch),
+        ),
+      ],
+    );
+    GestureBinding.instance.resamplingEnabled = true;
+    ui.window.onPointerDataPacket!(packet);
+
+    // Expected to stop resampling, but the timer keeps active if _timer?.cancel() not be called.
+    GestureBinding.instance.resamplingEnabled = false;
+  });
 }