Store the async-await compiled pub code directly in the repo.

sdk/lib/_internal/pub_generated/test/list_package_dirs/pubspec_error_test.dart

Index: sdk/lib/_internal/pub_generated/test/list_package_dirs/pubspec_error_test.dart
diff --git a/sdk/lib/_internal/pub_generated/test/list_package_dirs/pubspec_error_test.dart b/sdk/lib/_internal/pub_generated/test/list_package_dirs/pubspec_error_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..0287dcc8a575b94711ed3524c5d474b522104c61
--- /dev/null
+++ b/sdk/lib/_internal/pub_generated/test/list_package_dirs/pubspec_error_test.dart
@@ -0,0 +1,16 @@
+import 'package:path/path.dart' as path;
+import 'package:scheduled_test/scheduled_test.dart';
+import '../../lib/src/exit_codes.dart' as exit_codes;
+import '../../lib/src/io.dart';
+import '../descriptor.dart' as d;
+import '../test_pub.dart';
+main() {
+  initConfig();
+  integration("reports the pubspec path when there is an error in it", () {
+    d.dir(appPath, [d.file("pubspec.yaml", "some bad yaml")]).create();
+    schedulePub(args: ["list-package-dirs", "--format=json"], outputJson: {
+      "error": contains('Error on line 1'),
+      "path": canonicalize(path.join(sandboxDir, appPath, "pubspec.yaml"))
+    }, exitCode: exit_codes.DATA);
+  });
+}