[cupertino_ui] Migrate radio_test.dart to SemanticsHandle (#11981)

Part of flutter/flutter#182636 and flutter/flutter#188395

This PR:
* Removed the cross-import of `widgets/semantics_tester.dart`. Replaced `SemanticsTester` with `SemanticsHandle`.
* Removed `@Skip` annotation, all tests in this file has passed. `semantics_tester.dart` has existed in `cupertino_ui`, so we can directly import `semantics_tester.dart`;
* Moved the file to `test/` folder.

## Pre-Review Checklist

Author: Renzo-Olivares

…mporarily_disabled_tests/radio_test.dart …ckages/cupertino_ui/test/radio_test.dartpackages/cupertino_ui/temporarily_disabled_tests/radio_test.dart renamed to packages/cupertino_ui/test/radio_test.dart packages/cupertino_ui/temporarily_disabled_tests/radio_test.dart renamed to packages/cupertino_ui/test/radio_test.dart

@@ -2,9 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-@Skip(
-  'This file is skipped due to a cross-import that needs to be fixed. Tracked in https://github.com/flutter/flutter/issues/177028.',
-)
 // reduced-test-set:
 //   This file is run as part of a reduced test set in CI on Mac and Windows
 //   machines.
@@ -18,8 +15,6 @@ import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
-import '../widgets/semantics_tester.dart';
-
 void main() {
   testWidgets('Radio control test', (WidgetTester tester) async {
     final Key key = UniqueKey();
@@ -146,7 +141,7 @@ void main() {
   });
 
   testWidgets('Radio selected semantics - platform adaptive', (WidgetTester tester) async {
-    final semantics = SemanticsTester(tester);
+    final SemanticsHandle handle = tester.ensureSemantics();
 
     await tester.pumpWidget(
       CupertinoApp(
@@ -158,29 +153,26 @@ void main() {
         defaultTargetPlatform == TargetPlatform.iOS ||
         defaultTargetPlatform == TargetPlatform.macOS;
     expect(
-      semantics,
-      includesNodeWith(
-        flags: <SemanticsFlag>[
-          SemanticsFlag.isInMutuallyExclusiveGroup,
-          SemanticsFlag.hasCheckedState,
-          SemanticsFlag.hasEnabledState,
-          SemanticsFlag.isEnabled,
-          SemanticsFlag.isFocusable,
-          SemanticsFlag.isChecked,
-          if (isApple) SemanticsFlag.hasSelectedState,
-          if (isApple) SemanticsFlag.isSelected,
-        ],
-        actions: <SemanticsAction>[
-          SemanticsAction.tap,
-          if (defaultTargetPlatform != TargetPlatform.iOS) SemanticsAction.focus,
-        ],
-      ),
-    );
-    semantics.dispose();
+      tester.getSemantics(find.byType(CupertinoRadio<int>)),
+      isSemantics(
+        isInMutuallyExclusiveGroup: true,
+        hasCheckedState: true,
+        hasEnabledState: true,
+        isEnabled: true,
+        isFocusable: true,
+        isChecked: true,
+        hasSelectedState: isApple ? true : null,
+        isSelected: isApple ? true : null,
+        hasTapAction: true,
+        hasFocusAction: defaultTargetPlatform != TargetPlatform.iOS ? true : null,
+      ),
+    );
+
+    handle.dispose();
   }, variant: TargetPlatformVariant.all());
 
   testWidgets('Radio semantics', (WidgetTester tester) async {
-    final semantics = SemanticsTester(tester);
+    final SemanticsHandle handle = tester.ensureSemantics();
 
     await tester.pumpWidget(
       CupertinoApp(
@@ -262,11 +254,12 @@ void main() {
       ),
     );
 
-    semantics.dispose();
+    handle.dispose();
   });
 
   testWidgets('has semantic events', (WidgetTester tester) async {
-    final semantics = SemanticsTester(tester);
+    final SemanticsHandle handle = tester.ensureSemantics();
+
     final Key key = UniqueKey();
     dynamic semanticEvent;
     int? radioValue = 2;
@@ -303,7 +296,7 @@ void main() {
     });
     expect(object.debugSemantics!.getSemanticsData().hasAction(SemanticsAction.tap), true);
 
-    semantics.dispose();
+    handle.dispose();
     tester.binding.defaultBinaryMessenger.setMockDecodedMessageHandler<dynamic>(
       SystemChannels.accessibility,
       null,