Replace using MockSdk with FolderBasedDartSdk + summaries in AbstractContextTest(s).

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 6375766f0757320dcfa7e5218af6aa8e00d755d9..08273912dcadb50af6b5f0cfe88bfa414b7df918 100644
--- a/pkg/analysis_server/test/abstract_context.dart
+++ b/pkg/analysis_server/test/abstract_context.dart
@@ -10,10 +10,12 @@ 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';
@@ -44,7 +46,10 @@ Element findChildElement(Element root, String name, [ElementKind kind]) {
 typedef void _ElementVisitorFunction(Element element);
 
 class AbstractContextTest {
-  static final DartSdk SDK = new MockSdk();
+  static final DartSdk SDK = new FolderBasedDartSdk(
+      PhysicalResourceProvider.INSTANCE,
+      FolderBasedDartSdk.defaultSdkDirectory(PhysicalResourceProvider.INSTANCE))
+    ..useSummary = true;
   static final UriResolver SDK_RESOLVER = new DartUriResolver(SDK);
 
   MemoryResourceProvider provider;