[qa] make create_confirmed_utxos calculate fees

Summary: As per title. Depends on D1632

Test Plan: ./test/functional/test_runner.py

Reviewers: #bitcoin_abc, jasonbcox

Reviewed By: #bitcoin_abc, jasonbcox

Subscribers: jasonbcox, teamcity

Differential Revision: https://reviews.bitcoinabc.org/D1633