Add completion tests for the new analysis driver.

pkg/analysis_server/test/services/completion/dart/variable_name_contributor_test.dart

Index: pkg/analysis_server/test/services/completion/dart/variable_name_contributor_test.dart
diff --git a/pkg/analysis_server/test/services/completion/dart/variable_name_contributor_test.dart b/pkg/analysis_server/test/services/completion/dart/variable_name_contributor_test.dart
index a5c4446caed38fe1b87eca3251f6ac594880c10c..316e1d89a029694a82022234778244cb6aa51959 100644
--- a/pkg/analysis_server/test/services/completion/dart/variable_name_contributor_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/variable_name_contributor_test.dart
@@ -14,6 +14,7 @@ import 'completion_contributor_util.dart';
 main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(VariableNameContributorTest);
+    defineReflectiveTests(VariableNameContributorTest_Driver);
   });
 }
 
@@ -244,3 +245,9 @@ class VariableNameContributorTest extends DartCompletionContributorTest {
     assertSuggestName('a');
   }
 }
+
+@reflectiveTest
+class VariableNameContributorTest_Driver extends VariableNameContributorTest {
+  @override
+  bool get enableNewAnalysisDriver => true;
+}