Fix sample code crash, add test (#133812)

Fixes https://github.com/flutter/flutter/issues/133402

On web `1 << 32` crashes, 31 is the maximum.

dev/bots/check_code_samples.dart

@@ -405,7 +405,6 @@ final Set<String> _knownMissingTests = <String>{
   'examples/api/test/widgets/animated_switcher/animated_switcher.0_test.dart',
   'examples/api/test/widgets/transitions/relative_positioned_transition.0_test.dart',
   'examples/api/test/widgets/transitions/positioned_transition.0_test.dart',
-  'examples/api/test/widgets/transitions/listenable_builder.3_test.dart',
   'examples/api/test/widgets/transitions/sliver_fade_transition.0_test.dart',
   'examples/api/test/widgets/transitions/align_transition.0_test.dart',
   'examples/api/test/widgets/transitions/fade_transition.0_test.dart',

examples/api/lib/widgets/transitions/listenable_builder.3.dart

@@ -39,7 +39,7 @@ class _ListenableBuilderExampleState extends State<ListenableBuilderExample> {
         appBar: AppBar(title: const Text('ListenableBuilder Example')),
         body: ListBody(listNotifier: _listNotifier),
         floatingActionButton: FloatingActionButton(
-          onPressed: () => _listNotifier.add(_random.nextInt(1 << 32)), // 1 << 32 is the maximum supported value
+          onPressed: () => _listNotifier.add(_random.nextInt(1 << 31)), // 1 << 31 is the maximum supported value
           child: const Icon(Icons.add),
         ),
       ),

examples/api/test/widgets/transitions/listenable_builder.3_test.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/material.dart';
+import 'package:flutter_api_samples/widgets/transitions/listenable_builder.3.dart' as example;
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets('Tapping FAB adds to values', (WidgetTester tester) async {
+    await tester.pumpWidget(const example.ListenableBuilderExample());
+
+    final Finder listContent = find.byWidgetPredicate((Widget widget) => widget is example.ListBody);
+
+    expect(find.text('Current values:'), findsOneWidget);
+    expect(find.byIcon(Icons.add), findsOneWidget);
+    expect(
+      (tester.widget(listContent) as example.ListBody).listNotifier.values.isEmpty,
+      isTrue,
+    );
+
+    await tester.tap(find.byType(FloatingActionButton).first);
+    await tester.pumpAndSettle();
+    expect(
+      (tester.widget(listContent) as example.ListBody).listNotifier.values.isEmpty,
+      isFalse,
+    );
+    expect(
+      (tester.widget(listContent) as example.ListBody).listNotifier.values,
+      <int>[1464685455],
+    );
+    expect(find.text('1464685455'), findsOneWidget);
+  });
+}