remove context and flutter version bump (#2915)

.ci/flutter_master.version

@@ -1 +1 @@
-a570fd25d83b1491952cd3d58b31e11040bb2334
+e52449b641276c1cece462dd495fa16158549107

packages/go_router/test/test_helpers.dart

@@ -6,7 +6,6 @@
 
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
-import 'package:flutter/src/foundation/diagnostics.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:go_router/go_router.dart';
 
@@ -219,102 +218,6 @@ Widget dummy(BuildContext context, GoRouterState state) => const DummyScreen();
 
 final GlobalKey<NavigatorState> navigatorKey = GlobalKey<NavigatorState>();
 
-class DummyBuildContext implements BuildContext {
-  @override
-  bool get debugDoingBuild => throw UnimplementedError();
-
-  @override
-  InheritedWidget dependOnInheritedElement(InheritedElement ancestor,
-      {Object aspect = 1}) {
-    throw UnimplementedError();
-  }
-
-  @override
-  T? dependOnInheritedWidgetOfExactType<T extends InheritedWidget>(
-      {Object? aspect}) {
-    throw UnimplementedError();
-  }
-
-  @override
-  DiagnosticsNode describeElement(String name,
-      {DiagnosticsTreeStyle style = DiagnosticsTreeStyle.errorProperty}) {
-    throw UnimplementedError();
-  }
-
-  @override
-  List<DiagnosticsNode> describeMissingAncestor(
-      {required Type expectedAncestorType}) {
-    throw UnimplementedError();
-  }
-
-  @override
-  DiagnosticsNode describeOwnershipChain(String name) {
-    throw UnimplementedError();
-  }
-
-  @override
-  DiagnosticsNode describeWidget(String name,
-      {DiagnosticsTreeStyle style = DiagnosticsTreeStyle.errorProperty}) {
-    throw UnimplementedError();
-  }
-
-  @override
-  void dispatchNotification(Notification notification) {
-    throw UnimplementedError();
-  }
-
-  @override
-  T? findAncestorRenderObjectOfType<T extends RenderObject>() {
-    throw UnimplementedError();
-  }
-
-  @override
-  T? findAncestorStateOfType<T extends State<StatefulWidget>>() {
-    throw UnimplementedError();
-  }
-
-  @override
-  T? findAncestorWidgetOfExactType<T extends Widget>() {
-    throw UnimplementedError();
-  }
-
-  @override
-  RenderObject? findRenderObject() {
-    throw UnimplementedError();
-  }
-
-  @override
-  T? findRootAncestorStateOfType<T extends State<StatefulWidget>>() {
-    throw UnimplementedError();
-  }
-
-  @override
-  InheritedElement?
-      getElementForInheritedWidgetOfExactType<T extends InheritedWidget>() {
-    throw UnimplementedError();
-  }
-
-  @override
-  BuildOwner? get owner => throw UnimplementedError();
-
-  @override
-  Size? get size => throw UnimplementedError();
-
-  @override
-  void visitAncestorElements(bool Function(Element element) visitor) {}
-
-  @override
-  void visitChildElements(ElementVisitor visitor) {}
-
-  @override
-  Widget get widget => throw UnimplementedError();
-
-  @override
-  // TODO(bparrishMines): Remove once this parameter is available on Flutter stable.
-  // ignore: override_on_non_overriding_member
-  bool get mounted => throw UnimplementedError();
-}
-
 class DummyStatefulWidget extends StatefulWidget {
   const DummyStatefulWidget({super.key});