[CI tests] Rename ecash-coinselect to ecash-coinselect-tests
Summary: Follow the convention of the other -tests builds. This script runs tests, does not build the pkg.
Test Plan: ./contrib/teamcity/build-configurations.py ecash-coinselect-tests
Reviewers: #bitcoin_abc, Fabien
Reviewed By: #bitcoin_abc, Fabien
Differential Revision: https://reviews.bitcoinabc.org/D15636