Remove the old task model

pkg/analyzer/test/src/mock_sdk.dart

Index: pkg/analyzer/test/src/mock_sdk.dart
diff --git a/pkg/analyzer/test/src/mock_sdk.dart b/pkg/analyzer/test/src/mock_sdk.dart
index d4f6ac1193f037363911e10f7562804c7c7a4fc6..91d89f02157cbfafc7c807c61a5b4526083d8114 100644
--- a/pkg/analyzer/test/src/mock_sdk.dart
+++ b/pkg/analyzer/test/src/mock_sdk.dart
@@ -6,7 +6,7 @@ library test.src.mock_sdk;
 
 import 'package:analyzer/file_system/file_system.dart' as resource;
 import 'package:analyzer/file_system/memory_file_system.dart' as resource;
-import 'package:analyzer/src/context/context.dart' as newContext;
+import 'package:analyzer/src/context/context.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/sdk.dart';
 import 'package:analyzer/src/generated/source.dart';
@@ -201,11 +201,7 @@ class HtmlElement {}
   @override
   AnalysisContext get context {
     if (_analysisContext == null) {
-      if (AnalysisEngine.instance.useTaskModel) {
-        _analysisContext = new newContext.SdkAnalysisContext();
-      } else {
-        _analysisContext = new SdkAnalysisContext();
-      }
+      _analysisContext = new SdkAnalysisContext();
       SourceFactory factory = new SourceFactory([new DartUriResolver(this)]);
       _analysisContext.sourceFactory = factory;
       ChangeSet changeSet = new ChangeSet();