[cmake] Use terminal when runnign integration tests

Summary: This is recomanded for long running commands that output things as they go.

Test Plan:

ninja check-all

Observe that the output of the test_runner.py appears on the console.

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D4534