Remove the non-driver versions of several tests

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

Index: pkg/analysis_server/test/services/completion/dart/label_contributor_test.dart
diff --git a/pkg/analysis_server/test/services/completion/dart/label_contributor_test.dart b/pkg/analysis_server/test/services/completion/dart/label_contributor_test.dart
index ea65d56ada69aa5a9d93641ef35805092f9c45b2..c38c96f11600c2b64e3f412404530571a556c907 100644
--- a/pkg/analysis_server/test/services/completion/dart/label_contributor_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/label_contributor_test.dart
@@ -14,12 +14,14 @@ import 'completion_contributor_util.dart';
 main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(LabelContributorTest);
-    defineReflectiveTests(LabelContributorTest_Driver);
   });
 }
 
 @reflectiveTest
 class LabelContributorTest extends DartCompletionContributorTest {
+  @override
+  bool get enableNewAnalysisDriver => true;
+
   CompletionSuggestion assertSuggestLabel(String name,
       {int relevance: DART_RELEVANCE_DEFAULT,
       CompletionSuggestionKind kind: CompletionSuggestionKind.IDENTIFIER}) {
@@ -320,9 +322,3 @@ void main() {
     assertSuggestLabel('foo');
   }
 }
-
-@reflectiveTest
-class LabelContributorTest_Driver extends LabelContributorTest {
-  @override
-  bool get enableNewAnalysisDriver => true;
-}