Use a mock SDK for most analysis server tests.

pkg/analysis_server/test/domain_analysis_test.dart

Index: pkg/analysis_server/test/domain_analysis_test.dart
diff --git a/pkg/analysis_server/test/domain_analysis_test.dart b/pkg/analysis_server/test/domain_analysis_test.dart
index d3b3720e66a6395436812c16aee8b91071dc0b31..a4df7bb927fe06cd6c7114c840cc6938a0cdd3ca 100644
--- a/pkg/analysis_server/test/domain_analysis_test.dart
+++ b/pkg/analysis_server/test/domain_analysis_test.dart
@@ -28,6 +28,7 @@ main() {
   setUp(() {
     serverChannel = new MockServerChannel();
     server = new AnalysisServer(serverChannel, resourceProvider);
+    server.defaultSdk = new MockSdk();
     handler = new AnalysisDomainHandler(server);
   });
 
@@ -184,6 +185,7 @@ class AnalysisTestHelper {
     serverChannel = new MockServerChannel();
     resourceProvider = new MemoryResourceProvider();
     server = new AnalysisServer(serverChannel, resourceProvider);
+    server.defaultSdk = new MockSdk();
     handler = new AnalysisDomainHandler(server);
     // listen for notifications
     Stream<Notification> notificationStream = serverChannel.notificationController.stream;