Remove the non-driver versions of several tests

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 316e1d89a029694a82022234778244cb6aa51959..6a5915674b0357c9b7cf51594e656bea03306982 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
@@ -14,13 +14,15 @@ import 'completion_contributor_util.dart';
 main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(VariableNameContributorTest);
-    defineReflectiveTests(VariableNameContributorTest_Driver);
   });
 }
 
 @reflectiveTest
 class VariableNameContributorTest extends DartCompletionContributorTest {
   @override
+  bool get enableNewAnalysisDriver => true;
+
+  @override
   DartCompletionContributor createContributor() {
     return new VariableNameContributor();
   }
@@ -245,9 +247,3 @@ class VariableNameContributorTest extends DartCompletionContributorTest {
     assertSuggestName('a');
   }
 }
-
-@reflectiveTest
-class VariableNameContributorTest_Driver extends VariableNameContributorTest {
-  @override
-  bool get enableNewAnalysisDriver => true;
-}