Fix the code completion timing test

pkg/analyzer/lib/source/pub_package_map_provider.dart

Index: pkg/analyzer/lib/source/pub_package_map_provider.dart
diff --git a/pkg/analyzer/lib/source/pub_package_map_provider.dart b/pkg/analyzer/lib/source/pub_package_map_provider.dart
index 732ef816e4d87da35c11afab1c2b10981b624768..c0d34316d114f0d9af9731b02cdb689737b9a74f 100644
--- a/pkg/analyzer/lib/source/pub_package_map_provider.dart
+++ b/pkg/analyzer/lib/source/pub_package_map_provider.dart
@@ -55,7 +55,7 @@ class PubPackageMapProvider implements PackageMapProvider {
       AnalysisEngine.instance.logger.logInformation(
           "Error running pub $PUB_LIST_COMMAND\n$exception\n$stackTrace");
     }
-    if (result.exitCode != 0) {
+    if (result == null || result.exitCode != 0) {
       AnalysisEngine.instance.logger.logInformation(
           "pub $PUB_LIST_COMMAND failed: exit code ${result.exitCode}");
       return _error(folder);