[Benchmark: platform_views_layout] show and hide more PlatformViews (#110688)

dev/benchmarks/platform_views_layout/test_driver/scroll_perf_test.dart

@@ -33,6 +33,7 @@ void main() {
         final SerializableFinder list = find.byValueKey(listKey);
         expect(list, isNotNull);
 
+        for (int j = 0; j < 5; j ++) {
           // Scroll down
           for (int i = 0; i < 5; i += 1) {
             await driver.scroll(list, 0.0, -300.0, const Duration(milliseconds: 300));
@@ -44,6 +45,7 @@ void main() {
             await driver.scroll(list, 0.0, 300.0, const Duration(milliseconds: 300));
             await Future<void>.delayed(const Duration(milliseconds: 500));
           }
+        }
       });
 
       final TimelineSummary summary = TimelineSummary.summarize(timeline);