Fix completion tests that attempted to resolve a library.

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

Index: pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart
diff --git a/pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart b/pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart
index 62deed1819cbcb9eebc2cc217530bd1bda672dfe..4c03a4f031963356da3e1629ea3929238df0538d 100644
--- a/pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart
+++ b/pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart
@@ -566,8 +566,10 @@ abstract class DartCompletionContributorTest extends AbstractContextTest {
 
   void resolveSource(String path, String content) {
     Source libSource = addSource(path, content);
-    var target = new LibrarySpecificUnit(libSource, libSource);
-    context.computeResult(target, RESOLVED_UNIT);
+    if (!enableNewAnalysisDriver) {
+      var target = new LibrarySpecificUnit(libSource, libSource);
+      context.computeResult(target, RESOLVED_UNIT);
+    }
   }
 
   @override