Fix shrine (#89698)

dev/integration_tests/flutter_gallery/lib/demo/shrine/app.dart

@@ -37,6 +37,11 @@ class _ShrineAppState extends State<ShrineApp> with SingleTickerProviderStateMix
   @override
   Widget build(BuildContext context) {
     return MaterialApp(
+      // The automatically applied scrollbars on desktop can cause a crash for
+      // demos where many scrollables are all attached to the same
+      // PrimaryScrollController. The gallery needs to be migrated before
+      // enabling this. https://github.com/flutter/gallery/issues/523
+      scrollBehavior: const MaterialScrollBehavior().copyWith(scrollbars: false),
       title: 'Shrine',
       home: HomePage(
         backdrop: Backdrop(

dev/integration_tests/flutter_gallery/test/smoke_test.dart

@@ -176,7 +176,11 @@ Future<void> smokeGallery(WidgetTester tester) async {
 }
 
 void main() {
-  testWidgets('Flutter Gallery app smoke test', smokeGallery);
+  testWidgets(
+    'Flutter Gallery app smoke test',
+    smokeGallery,
+    variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.android, TargetPlatform.macOS }),
+  );
 
   testWidgets('Flutter Gallery app smoke test with semantics', (WidgetTester tester) async {
     RendererBinding.instance!.setSemanticsEnabled(true);