Make Analysis Server tests use MockSdk again.

pkg/analysis_server/test/abstract_context.dart

Index: pkg/analysis_server/test/abstract_context.dart
diff --git a/pkg/analysis_server/test/abstract_context.dart b/pkg/analysis_server/test/abstract_context.dart
index b0750f2c4c5b96e58dcb3ce20a92dd485fbe69fe..16ad89c89cbe919eb502bca9401f5196d8c3df00 100644
--- a/pkg/analysis_server/test/abstract_context.dart
+++ b/pkg/analysis_server/test/abstract_context.dart
@@ -6,18 +6,17 @@ library testing.abstract_context;
 
 import 'dart:async';
 
+import 'mock_sdk.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/visitor.dart';
 import 'package:analyzer/exception/exception.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
-import 'package:analyzer/file_system/physical_file_system.dart';
 import 'package:analyzer/source/package_map_resolver.dart';
 import 'package:analyzer/src/dart/analysis/byte_store.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart';
 import 'package:analyzer/src/dart/analysis/file_state.dart';
-import 'package:analyzer/src/dart/sdk/sdk.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/engine.dart' as engine;
 import 'package:analyzer/src/generated/sdk.dart';
@@ -46,10 +45,7 @@ Element findChildElement(Element root, String name, [ElementKind kind]) {
 typedef void _ElementVisitorFunction(Element element);
 
 class AbstractContextTest {
-  static final DartSdk SDK = new FolderBasedDartSdk(
-      PhysicalResourceProvider.INSTANCE,
-      FolderBasedDartSdk.defaultSdkDirectory(PhysicalResourceProvider.INSTANCE))
-    ..useSummary = true;
+  static final DartSdk SDK = new MockSdk();
   static final UriResolver SDK_RESOLVER = new DartUriResolver(SDK);
 
   MemoryResourceProvider provider;