Remove uses of the old plugin model from the analysis server

pkg/analysis_server/test/domain_execution_test.dart

Index: pkg/analysis_server/test/domain_execution_test.dart
diff --git a/pkg/analysis_server/test/domain_execution_test.dart b/pkg/analysis_server/test/domain_execution_test.dart
index f77099708ad1b8d93f5b374ff45a589a13156b20..b46daaab75a6322cfd2191041c18bac8c2aa2599 100644
--- a/pkg/analysis_server/test/domain_execution_test.dart
+++ b/pkg/analysis_server/test/domain_execution_test.dart
@@ -6,13 +6,11 @@ import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/domain_execution.dart';
-import 'package:analysis_server/src/plugin/server_plugin.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
 import 'package:analyzer/instrumentation/instrumentation.dart';
 import 'package:analyzer/src/generated/sdk.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/source_io.dart';
-import 'package:plugin/manager.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
@@ -29,14 +27,10 @@ main() {
     ExecutionDomainHandler handler;
 
     setUp(() {
-      ExtensionManager manager = new ExtensionManager();
-      ServerPlugin serverPlugin = new ServerPlugin();
-      manager.processPlugins([serverPlugin]);
       server = new AnalysisServer(
           new MockServerChannel(),
           provider,
           new MockPackageMapProvider(),
-          serverPlugin,
           new AnalysisServerOptions(),
           new DartSdkManager('', false),
           InstrumentationService.NULL_SERVICE);