Switch imports from test_api to focused libaries (#125854)

Move imports of API available in `hooks.dart` or `scaffolding.dart` to use those more narrow libraries.

Move imports of APIs from `package:matcher` to import directly. The next major version of `test_api` will remove the exports of `matcher` APIs.

packages/flutter_test/lib/src/_binding_io.dart

@@ -9,8 +9,7 @@ import 'dart:io';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 import 'package:path/path.dart' as path;
-// ignore: deprecated_member_use
-import 'package:test_api/test_api.dart' as test_package;
+import 'package:test_api/scaffolding.dart' as test_package;
 
 import 'binding.dart';
 

packages/flutter_test/lib/src/binding.dart

@@ -13,9 +13,9 @@ import 'package:flutter/rendering.dart';
 import 'package:flutter/scheduler.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
+import 'package:matcher/expect.dart' show fail;
 import 'package:stack_trace/stack_trace.dart' as stack_trace;
-import 'package:test_api/expect.dart' show fail;
-import 'package:test_api/test_api.dart' as test_package show Timeout; // ignore: deprecated_member_use
+import 'package:test_api/scaffolding.dart' as test_package show Timeout;
 import 'package:vector_math/vector_math_64.dart';
 
 import '_binding_io.dart' if (dart.library.html) '_binding_web.dart' as binding;

packages/flutter_test/lib/src/buffer_matcher.dart

@@ -4,9 +4,9 @@
 
 import 'dart:typed_data';
 
+import 'package:matcher/expect.dart' show Description;
 import 'package:matcher/src/expect/async_matcher.dart'; // ignore: implementation_imports
-// ignore: deprecated_member_use
-import 'package:test_api/test_api.dart' show Description, TestFailure;
+import 'package:test_api/hooks.dart' show TestFailure;
 
 import 'goldens.dart';
 

packages/flutter_test/lib/src/goldens.dart

@@ -6,7 +6,6 @@ import 'dart:typed_data';
 import 'dart:ui';
 
 import 'package:path/path.dart' as path;
-import 'package:test_api/test_api.dart'; // ignore: deprecated_member_use
 
 import '_goldens_io.dart' if (dart.library.html) '_goldens_web.dart' as goldens;
 

packages/flutter_test/lib/src/test_compat.dart

@@ -5,6 +5,7 @@
 import 'dart:async';
 
 import 'package:meta/meta.dart';
+import 'package:test_api/scaffolding.dart' show Timeout;
 import 'package:test_api/src/backend/declarer.dart'; // ignore: implementation_imports
 import 'package:test_api/src/backend/group.dart'; // ignore: implementation_imports
 import 'package:test_api/src/backend/group_entry.dart'; // ignore: implementation_imports
@@ -16,8 +17,6 @@ import 'package:test_api/src/backend/state.dart'; // ignore: implementation_impo
 import 'package:test_api/src/backend/suite.dart'; // ignore: implementation_imports
 import 'package:test_api/src/backend/suite_platform.dart'; // ignore: implementation_imports
 import 'package:test_api/src/backend/test.dart'; // ignore: implementation_imports
-// ignore: deprecated_member_use
-import 'package:test_api/test_api.dart';
 
 // ignore: deprecated_member_use
 export 'package:test_api/fake.dart' show Fake;

packages/flutter_test/lib/src/test_exception_reporter.dart

@@ -4,9 +4,7 @@
 
 import 'package:flutter/foundation.dart';
 import 'package:stack_trace/stack_trace.dart' as stack_trace;
-
-// ignore: deprecated_member_use
-import 'package:test_api/test_api.dart' as test_package;
+import 'package:test_api/scaffolding.dart' as test_package;
 
 /// Signature for the [reportTestException] callback.
 typedef TestExceptionReporter = void Function(FlutterErrorDetails details, String testDescription);

packages/flutter_test/lib/src/widget_tester.dart

@@ -11,10 +11,7 @@ import 'package:flutter/scheduler.dart';
 import 'package:flutter/services.dart';
 import 'package:matcher/expect.dart' as matcher_expect;
 import 'package:meta/meta.dart';
-
-// The test_api package is not for general use... it's literally for our use.
-// ignore: deprecated_member_use
-import 'package:test_api/test_api.dart' as test_package;
+import 'package:test_api/scaffolding.dart' as test_package;
 
 import 'all_elements.dart';
 import 'binding.dart';
@@ -686,7 +683,7 @@ class WidgetTester extends WidgetController implements HitTestDispatcher, Ticker
       final WidgetsBinding binding = this.binding;
       if (binding is LiveTestWidgetsFlutterBinding &&
           binding.framePolicy == LiveTestWidgetsFlutterBindingFramePolicy.benchmark) {
-        test_package.fail(
+        matcher_expect.fail(
           'When using LiveTestWidgetsFlutterBindingFramePolicy.benchmark, '
           'hasScheduledFrame is never set to true. This means that pumpAndSettle() '
           'cannot be used, because it has no way to know if the application has '