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

sdk/lib/_internal/pub_generated/test/global/activate/missing_git_repo_test.dart

+import 'package:scheduled_test/scheduled_test.dart';
+import '../../test_pub.dart';
+main() {
+  initConfig();
+  integration('fails if the Git repo does not exist', () {
+    ensureGit();
+    schedulePub(
+        args: ["global", "activate", "-sgit", "../nope.git"],
+        error: contains("repository '../nope.git' does not exist"),
+        exitCode: 1);
+  });
+}