analyzer_testing: deprecate PubPackageResolutionTest.addKernelPackageDep

This shared mock did not carry its weight. It should have more use cases
in order to support as a pre-made mock package. We can instead make a
simple custom mock package in the one test that used it.

Change-Id: I9877b114918bc42f5b72616b91085adecf6c194b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/460500
Reviewed-by: Konstantin Shcheglov <[email protected]>
Commit-Queue: Samuel Rawlins <[email protected]>

Author: srawlins

pkg/analyzer_testing/CHANGELOG.md

@@ -4,6 +4,8 @@
   analysis options file used in testing specifies a `true` value for
   `propagate-linter-exceptions`. This ensures that when tests are run,
   exceptions that occur while processing lint rules will cause the test to fail.
+- Deprecate `PubPackageResolutionTest.addKernelPackageDep`. A mock kernel
+  package can still be written with `PubPackageResolutionTest.newPackage`.
 
 ## 0.1.7
 

pkg/analyzer_testing/lib/src/analysis_rule/pub_package_resolution.dart

@@ -235,6 +235,10 @@ class PubPackageResolutionTest with MockPackagesMixin, ResourceProviderMixin {
   /// Adds the 'kernel' package as a dependency to the package-under-test.
   ///
   /// This allows various `package:kernel/` imports to resolve.
+  @Deprecated(
+    'The mock kernel package is deprecated; use '
+    '`PubPackageResolutionTest.newPackage` to make a custom mock',
+  )
   bool get addKernelPackageDep => false;
 
   /// Adds the 'meta' package as a dependency to the package-under-test.

pkg/linter/test/rules/erase_dart_type_extension_types_test.dart

@@ -15,10 +15,21 @@ void main() {
 @reflectiveTest
 class EraseDartTypeExtensionTypesTest extends LintRuleTest {
   @override
-  bool get addKernelPackageDep => true;
+  String get lintRule => LintNames.erase_dart_type_extension_types;
 
   @override
-  String get lintRule => LintNames.erase_dart_type_extension_types;
+  void setUp() {
+    newPackage('kernel').addFile('lib/ast.dart', r'''
+library kernel.ast;
+
+abstract class Node {}
+
+class DartType extends Node {}
+
+class InterfaceType extends DartType {}
+''');
+    super.setUp();
+  }
 
   test_isDartType() async {
     await assertDiagnostics(