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

Author: Chris Yang

dev/benchmarks/platform_views_layout/test_driver/scroll_perf_test.dart

@@ -33,16 +33,18 @@ void main() {
         final SerializableFinder list = find.byValueKey(listKey);
         expect(list, isNotNull);
 
-        // Scroll down
-        for (int i = 0; i < 5; i += 1) {
-          await driver.scroll(list, 0.0, -300.0, const Duration(milliseconds: 300));
-          await Future<void>.delayed(const Duration(milliseconds: 500));
-        }
-
-        // Scroll up
-        for (int i = 0; i < 5; i += 1) {
-          await driver.scroll(list, 0.0, 300.0, const Duration(milliseconds: 300));
-          await Future<void>.delayed(const Duration(milliseconds: 500));
+        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));
+            await Future<void>.delayed(const Duration(milliseconds: 500));
+          }
+
+          // Scroll up
+          for (int i = 0; i < 5; i += 1) {
+            await driver.scroll(list, 0.0, 300.0, const Duration(milliseconds: 300));
+            await Future<void>.delayed(const Duration(milliseconds: 500));
+          }
         }
       });