[wildcards] unnecessary_final tests

Fixes #55920

See also https://github.com/dart-lang/linter/issues/4969

Change-Id: Id70834d6b71a268ed6037203124ae10a5eb1d592
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/375082
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Phil Quitslund <[email protected]>

Author: pq

pkg/linter/test/rules/unnecessary_final_test.dart

@@ -73,6 +73,29 @@ void f() {
     ]);
   }
 
+  test_localVariable_final_wildcard() async {
+    await assertDiagnostics(r'''
+void f() {
+  final _ = '';
+}
+''', [
+      lint(13, 5),
+    ]);
+  }
+
+  test_localVariable_final_wildcard_preWildcards() async {
+    await assertDiagnostics(r'''
+// @dart = 3.4
+// (pre wildcard-variables)
+
+void f() {
+  final _ = '';
+}
+''', [
+      lint(57, 5),
+    ]);
+  }
+
   test_localVariable_var() async {
     await assertNoDiagnostics(r'''
 void f() {