Fix move_folders_of_stuff (#826)

This is a fairly important test verifying whether the action of moving a
folder into a watched folder is correctly detected and processed. It was
disabled in
b43b45be8f.
The fact that it failed indicates a possible bug in change processing,
so in this PR, I'll re-enable the test, investigate why it fails, and
fix it.

tests/tests/serve.rs

@@ -145,7 +145,6 @@ fn edit_init() {
     });
 }
 
-#[ignore = "Does not pass on Github's runner"]
 #[test]
 fn move_folder_of_stuff() {
     run_serve_test("move_folder_of_stuff", |session, mut redactions| {