DeCo. Don't remove experiment from shared experimentsForTests.

Change-Id: If746609320113a42c161021f7c7328cf79bd46fc
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/465483
Reviewed-by: Phil Quitslund <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>

Author: scheglov

pkg/analyzer_testing/lib/experiments/experiments.dart

@@ -14,12 +14,12 @@ import 'package:analyzer/dart/analysis/features.dart';
 ///
 /// The flags in the list are kept in alphabetic order for ease of determining
 /// whether a given flag is already included.
-List<String> experimentsForTests = [
+List<String> experimentsForTests = List.unmodifiable([
   Feature.augmentations.enableString,
   Feature.enhanced_parts.enableString,
   Feature.macros.enableString,
   Feature.primary_constructors.enableString,
   Feature.private_named_parameters.enableString,
   Feature.static_extensions.enableString,
   Feature.variance.enableString,
-];
+]);

pkg/linter/test/rules/avoid_final_parameters_test.dart

@@ -18,8 +18,9 @@ void main() {
 @reflectiveTest
 class AvoidFinalParametersPrePrimaryConstructorsTest extends LintRuleTest {
   @override
-  List<String> get experiments =>
-      super.experiments..remove(Feature.primary_constructors.enableString);
+  List<String> get experiments => super.experiments
+      .where((e) => e != Feature.primary_constructors.enableString)
+      .toList();
 
   @override
   String get lintRule => LintNames.avoid_final_parameters;