Implement 'analysis.outline' for the new analysis driver.

pkg/analysis_server/test/integration/analysis/outline_test.dart

Index: pkg/analysis_server/test/integration/analysis/outline_test.dart
diff --git a/pkg/analysis_server/test/integration/analysis/outline_test.dart b/pkg/analysis_server/test/integration/analysis/outline_test.dart
index 3e2e5a40f02d9966a68abbc97e821501f74632dd..92865fff7bc6baab29e2f55802fe9a134a789da0 100644
--- a/pkg/analysis_server/test/integration/analysis/outline_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/outline_test.dart
@@ -89,10 +89,4 @@ class OutlineTest extends AbstractOutlineTest {}
 class OutlineTest_Driver extends AbstractOutlineTest {
   @override
   bool get enableNewAnalysisDriver => true;
-
-  @failingTest
-  test_outline() {
-    //  NoSuchMethodError: The getter 'element' was called on null.
-    return super.test_outline();
-  }
 }