tests: add functional tests for IPC interface

Co-Authored-By: ismaelsadeeq <ask4ismailsadiq@gmail.com>
Co-Authored-By: ryanofsky <ryan@ofsky.org>
Co-Authored-By: TheCharlatan <seb.kung@gmail.com>
Co-Authored-By: Sjors Provoost <sjors@sprovoost.nl>

test/functional/test_runner.py

@@ -339,6 +339,7 @@ BASE_SCRIPTS = [
     'rpc_scantxoutset.py',
     'feature_unsupported_utxo_db.py',
     'feature_logging.py',
+    'interface_ipc.py',
     'feature_anchors.py',
     'mempool_datacarrier.py',
     'feature_coinstatsindex.py',