HPCC-10372 - DeleteSuperFile possible crash

A regression introduced after 3.10.8, when DeleteSuperFile was
added to the transaction system, was causing DeletesuperFile
with delete-sub-files=true to crash sometimes.

The nested removeSubFile call was causing the parent action
(DeleteSuperFile) to be exected, which free the superfile,
leaving the super object in removeSubFile in a duff state.

Fix by using descend() / ascend() transaction calls to indicate
nested and delay both action until called in parent action.

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>