Get some tests running using the analysis driver

pkg/analysis_server/lib/src/single_context_manager.dart

Index: pkg/analysis_server/lib/src/single_context_manager.dart
diff --git a/pkg/analysis_server/lib/src/single_context_manager.dart b/pkg/analysis_server/lib/src/single_context_manager.dart
index fa99c96ac20ddcf857a9a68b97f9dfa30b1b3d54..5c28cae3f107194a03c863287b4d9dc613bd35ea 100644
--- a/pkg/analysis_server/lib/src/single_context_manager.dart
+++ b/pkg/analysis_server/lib/src/single_context_manager.dart
@@ -147,6 +147,12 @@ class SingleContextManager implements ContextManager {
   }
 
   @override
+  List<AnalysisDriver> getDriversInAnalysisRoot(Folder analysisRoot) {
+    throw new UnimplementedError(
+        'Unexpected invocation of getDriversInAnalysisRoot in SingleContextManager');
+  }
+
+  @override
   bool isIgnored(String path) {
     return !_isContainedIn(includedPaths, path) || _isExcludedPath(path);
   }