Remove uses of the old plugin model from the analysis server

pkg/analysis_server/test/edit/fixes_test.dart

Index: pkg/analysis_server/test/edit/fixes_test.dart
diff --git a/pkg/analysis_server/test/edit/fixes_test.dart b/pkg/analysis_server/test/edit/fixes_test.dart
index e78763ca4911957661fc260ed17423e0adf8c798..90732cdceef5bd9ec67297554794c8718a1bf408 100644
--- a/pkg/analysis_server/test/edit/fixes_test.dart
+++ b/pkg/analysis_server/test/edit/fixes_test.dart
@@ -12,7 +12,6 @@ import 'package:analyzer_plugin/protocol/protocol.dart' as plugin;
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:analyzer_plugin/protocol/protocol_generated.dart' as plugin;
 import 'package:analyzer_plugin/src/protocol/protocol_internal.dart' as plugin;
-import 'package:plugin/manager.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
@@ -29,8 +28,6 @@ class FixesTest extends AbstractAnalysisTest {
   @override
   void setUp() {
     super.setUp();
-    ExtensionManager manager = new ExtensionManager();
-    manager.processPlugins([server.serverPlugin]);
     handler = new EditDomainHandler(server);
   }