[flutter_tools] remove unused testbed method (#79459)

packages/flutter_tools/test/src/testbed.dart

@@ -22,10 +22,8 @@ import 'package:flutter_tools/src/dart/pub.dart';
 import 'package:flutter_tools/src/reporting/reporting.dart';
 import 'package:flutter_tools/src/version.dart';
 import 'package:flutter_tools/src/globals.dart' as globals;
-import 'package:meta/meta.dart';
 import 'package:process/process.dart';
 
-import 'common.dart' as tester;
 import 'context.dart';
 import 'fake_http_client.dart';
 import 'fakes.dart';
@@ -92,16 +90,6 @@ class Testbed {
   final FutureOr<void> Function() _setup;
   final Map<Type, Generator> _overrides;
 
-  /// Runs the `test` within a tool zone.
-  ///
-  /// Unlike [run], this sets up a test group on its own.
-  @isTest
-  void test<T>(String name, FutureOr<T> Function() test, {Map<Type, Generator> overrides}) {
-    tester.test(name, () {
-      return run(test, overrides: overrides);
-    });
-  }
-
   /// Runs `test` within a tool zone.
   ///
   /// `overrides` may be used to provide new context values for the single test