Revert "Integrate testWidgets with leak tracking. (#138057)" (#140502)

The PR is breaking the `flutter_test_performance` test and making the
tree red.

packages/flutter_test/lib/src/test_compat.dart

@@ -4,7 +4,6 @@
 
 import 'dart:async';
 
-import 'package:leak_tracker_flutter_testing/leak_tracker_flutter_testing.dart';
 import 'package:meta/meta.dart';
 import 'package:test_api/scaffolding.dart' show Timeout;
 import 'package:test_api/src/backend/declarer.dart'; // ignore: implementation_imports
@@ -164,7 +163,6 @@ void test(
   Map<String, dynamic>? onPlatform,
   int? retry,
 }) {
-  _configureTearDownForTestFile();
   _declarer.test(
     description.toString(),
     body,
@@ -188,7 +186,6 @@ void test(
 /// of running the group's tests.
 @isTestGroup
 void group(Object description, void Function() body, { dynamic skip, int? retry }) {
-  _configureTearDownForTestFile();
   _declarer.group(description.toString(), body, skip: skip, retry: retry);
 }
 
@@ -204,7 +201,6 @@ void group(Object description, void Function() body, { dynamic skip, int? retry
 /// Each callback at the top level or in a given group will be run in the order
 /// they were declared.
 void setUp(dynamic Function() body) {
-  _configureTearDownForTestFile();
   _declarer.setUp(body);
 }
 
@@ -222,7 +218,6 @@ void setUp(dynamic Function() body) {
 ///
 /// See also [addTearDown], which adds tear-downs to a running test.
 void tearDown(dynamic Function() body) {
-  _configureTearDownForTestFile();
   _declarer.tearDown(body);
 }
 
@@ -240,7 +235,6 @@ void tearDown(dynamic Function() body) {
 /// prefer [setUp], and only use [setUpAll] if the callback is prohibitively
 /// slow.
 void setUpAll(dynamic Function() body) {
-  _configureTearDownForTestFile();
   _declarer.setUpAll(body);
 }
 
@@ -256,27 +250,9 @@ void setUpAll(dynamic Function() body) {
 /// prefer [tearDown], and only use [tearDownAll] if the callback is
 /// prohibitively slow.
 void tearDownAll(dynamic Function() body) {
-  _configureTearDownForTestFile();
   _declarer.tearDownAll(body);
 }
 
-bool _isTearDownForTestFileConfigured = false;
-/// Configures `tearDownAll` after all user defined `tearDownAll` in the test file.
-///
-/// This function should be invoked in all functions, that may be invoked by user in the test file,
-/// to be invoked before any other `tearDownAll`.
-void _configureTearDownForTestFile() {
-  if (_isTearDownForTestFileConfigured) {
-    return;
-  }
-  _declarer.tearDownAll(_tearDownForTestFile);
-  _isTearDownForTestFileConfigured = true;
-}
-
-/// Tear down that should happen after all user defined tear down.
-Future<void> _tearDownForTestFile() async {
-  await maybeTearDownLeakTrackingForAll();
-}
 
 /// A reporter that prints each test on its own line.
 ///

packages/flutter_test/lib/src/widget_tester.dart

@@ -9,7 +9,6 @@ import 'package:flutter/material.dart' show Tooltip;
 import 'package:flutter/rendering.dart';
 import 'package:flutter/scheduler.dart';
 import 'package:flutter/services.dart';
-import 'package:leak_tracker_flutter_testing/leak_tracker_flutter_testing.dart';
 import 'package:matcher/expect.dart' as matcher_expect;
 import 'package:meta/meta.dart';
 import 'package:test_api/scaffolding.dart' as test_package;
@@ -117,18 +116,6 @@ E? _lastWhereOrNull<E>(Iterable<E> list, bool Function(E) test) {
 /// If the [tags] are passed, they declare user-defined tags that are implemented by
 /// the `test` package.
 ///
-/// The argument [experimentalLeakTesting] is experimental and is not recommended
-/// for use outside of the Flutter framework.
-/// When [experimentalLeakTesting] is set, it is used to leak track objects created
-/// during test execution.
-/// Otherwise [LeakTesting.settings] is used.
-/// Adjust [LeakTesting.settings] in flutter_test_config.dart
-/// (see https://github.com/flutter/flutter/blob/master/packages/flutter_test/lib/flutter_test.dart)
-/// for the entire package or folder, or in the test's main for a test file
-/// (don't use [setUp] or [setUpAll]).
-/// To turn off leak tracking just for one test, set [experimentalLeakTesting] to
-/// `LeakTrackingForTests.ignore()`.
-///
 /// ## Sample code
 ///
 /// ```dart
@@ -148,7 +135,6 @@ void testWidgets(
   TestVariant<Object?> variant = const DefaultTestVariant(),
   dynamic tags,
   int? retry,
-  LeakTesting? experimentalLeakTesting,
 }) {
   assert(variant.values.isNotEmpty, 'There must be at least one value to test in the testing variant.');
   final TestWidgetsFlutterBinding binding = TestWidgetsFlutterBinding.ensureInitialized();
@@ -179,11 +165,9 @@ void testWidgets(
             Object? memento;
             try {
               memento = await variant.setUp(value);
-              maybeSetupLeakTrackingForTest(experimentalLeakTesting, combinedDescription);
               await callback(tester);
             } finally {
               await variant.tearDown(value, memento);
-              maybeTearDownLeakTrackingForTest();
             }
             semanticsHandle?.dispose();
           },