Add some logs to catch flake (#109887)

dev/integration_tests/channels/test_driver/main_test.dart

@@ -18,6 +18,7 @@ void main() {
       final SerializableFinder statusField = find.byValueKey('status');
       int step = 0;
       while (await driver.getText(statusField) == 'ok') {
+        print('Tapping for step $step...');
         await driver.tap(stepButton);
         step++;
       }

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

@@ -360,7 +360,7 @@ mixin GestureBinding on BindingBase implements HitTestable, HitTestDispatcher, H
   void _handlePointerEventImmediately(PointerEvent event) {
     HitTestResult? hitTestResult;
     if (event is PointerDownEvent || event is PointerSignalEvent || event is PointerHoverEvent || event is PointerPanZoomStartEvent) {
-      assert(!_hitTests.containsKey(event.pointer));
+      assert(!_hitTests.containsKey(event.pointer), 'Pointer of $event unexpectedly has a HitTestResult associated with it.');
       hitTestResult = HitTestResult();
       hitTest(hitTestResult, event.position);
       if (event is PointerDownEvent || event is PointerPanZoomStartEvent) {