Remove the non-driver versions of several tests

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

Index: pkg/analysis_server/test/services/completion/dart/field_formal_contributor_test.dart
diff --git a/pkg/analysis_server/test/services/completion/dart/field_formal_contributor_test.dart b/pkg/analysis_server/test/services/completion/dart/field_formal_contributor_test.dart
index 9583d5fbc4c00a3298c92f907ec5adef96fd3107..f20a58579a15b9260b90ab5ccf2c7bb8a58dfb48 100644
--- a/pkg/analysis_server/test/services/completion/dart/field_formal_contributor_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/field_formal_contributor_test.dart
@@ -14,13 +14,15 @@ import 'completion_contributor_util.dart';
 main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(FieldFormalContributorTest);
-    defineReflectiveTests(FieldFormalContributorTest_Driver);
   });
 }
 
 @reflectiveTest
 class FieldFormalContributorTest extends DartCompletionContributorTest {
   @override
+  bool get enableNewAnalysisDriver => true;
+
+  @override
   DartCompletionContributor createContributor() {
     return new FieldFormalContributor();
   }
@@ -198,9 +200,3 @@ class FieldFormalContributorTest extends DartCompletionContributorTest {
     assertNotSuggested('x');
   }
 }
-
-@reflectiveTest
-class FieldFormalContributorTest_Driver extends FieldFormalContributorTest {
-  @override
-  bool get enableNewAnalysisDriver => true;
-}