Simplify RemovedLintUseTest and ReplacedLintUseTest tearDown().

We unregister all lint rules in `ContextResolutionTest`, so no need to do this manually in individual tests.

Change-Id: I7856c7cec5e077b7dd764c75a88c40623884a5cc
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/463980
Reviewed-by: Paul Berry <paulberry@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>
diff --git a/pkg/analyzer/test/src/diagnostics/removed_lint_use_test.dart b/pkg/analyzer/test/src/diagnostics/removed_lint_use_test.dart
index 50c2ef9..ccb3251 100644
--- a/pkg/analyzer/test/src/diagnostics/removed_lint_use_test.dart
+++ b/pkg/analyzer/test/src/diagnostics/removed_lint_use_test.dart
@@ -3,9 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:analyzer/src/diagnostic/diagnostic.dart' as diag;
-import 'package:analyzer/src/lint/registry.dart';
 import 'package:analyzer/src/test_utilities/lint_registration_mixin.dart';
-import 'package:linter/src/rules.dart' as linter;
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../dart/resolution/context_collection_resolution.dart';
@@ -22,7 +20,6 @@
   @override
   void setUp() {
     super.setUp();
-    linter.registerLintRules();
 
     // TODO(paulberry): remove as part of fixing
     // https://github.com/dart-lang/sdk/issues/62040.
@@ -33,14 +30,6 @@
 ''');
   }
 
-  @override
-  Future<void> tearDown() {
-    for (var rule in Registry.ruleRegistry.rules) {
-      Registry.ruleRegistry.unregisterLintRule(rule);
-    }
-    return super.tearDown();
-  }
-
   test_file() async {
     await assertErrorsInCode(
       r'''
diff --git a/pkg/analyzer/test/src/diagnostics/replaced_lint_use_test.dart b/pkg/analyzer/test/src/diagnostics/replaced_lint_use_test.dart
index 773cff3..9b4a9d1 100644
--- a/pkg/analyzer/test/src/diagnostics/replaced_lint_use_test.dart
+++ b/pkg/analyzer/test/src/diagnostics/replaced_lint_use_test.dart
@@ -7,9 +7,7 @@
 import 'package:analyzer/src/diagnostic/diagnostic.dart'
     as diag
     hide removedLint;
-import 'package:analyzer/src/lint/registry.dart';
 import 'package:analyzer/src/test_utilities/lint_registration_mixin.dart';
-import 'package:linter/src/rules.dart' as linter;
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../dart/resolution/context_collection_resolution.dart';
@@ -26,7 +24,6 @@
   @override
   void setUp() {
     super.setUp();
-    linter.registerLintRules();
 
     // TODO(paulberry): remove as part of fixing
     // https://github.com/dart-lang/sdk/issues/62040.
@@ -53,15 +50,6 @@
     );
   }
 
-  @override
-  Future<void> tearDown() {
-    unregisterLintRules();
-    for (var rule in Registry.ruleRegistry.rules) {
-      Registry.ruleRegistry.unregisterLintRule(rule);
-    }
-    return super.tearDown();
-  }
-
   test_file() async {
     await assertErrorsInCode(
       r'''