Remove obsolete flag to enable package support

pkg/analysis_server/test/context_manager_test.dart

Index: pkg/analysis_server/test/context_manager_test.dart
diff --git a/pkg/analysis_server/test/context_manager_test.dart b/pkg/analysis_server/test/context_manager_test.dart
index dc415095c1f20526a227f61190a0c0242cb7dc11..db575569b5b5bf94f974e068f3d119a678044bbd 100644
--- a/pkg/analysis_server/test/context_manager_test.dart
+++ b/pkg/analysis_server/test/context_manager_test.dart
@@ -90,17 +90,12 @@ class AbstractContextManagerTest {
     callbacks = new TestContextManagerCallbacks(resourceProvider);
     manager.callbacks = callbacks;
     resourceProvider.newFolder(projPath);
-    ContextManagerImpl.ENABLE_PACKAGESPEC_SUPPORT = true;
 
     // Options processing is required in context creation.
     ExtensionManager em = new ExtensionManager();
     em.processPlugins([AnalysisEngine.instance.optionsPlugin]);
   }
 
-  void tearDown() {
-    ContextManagerImpl.ENABLE_PACKAGESPEC_SUPPORT = false;
-  }
-
   test_analysis_options_parse_failure() async {
     // Create files.
     String libPath = newFolder([projPath, LIB_NAME]);