Fix recipes unit test.

When the recipes are running from cq the additional recipes folder was not being created.

Change-Id: I7e380889d915f65014ff0906ac2569e6a251aa77
Bug: https://github.com/flutter/flutter/issues/57068
Reviewed-on: https://flutter-review.googlesource.com/c/recipes/+/2824
Reviewed-by: Godofredo Contreras <godofredoc@google.com>