tests: Tests for inactive HD chains

test cases are added for inactive HD chains: a basic case, a case
where the wallet is encrypted, and a case for the 21605 segfault.

test/functional/test_runner.py

@@ -279,6 +279,7 @@ BASE_SCRIPTS = [
     'wallet_send.py --descriptors',
     'wallet_create_tx.py --descriptors',
     'wallet_taproot.py',
+    'wallet_inactive_hdchains.py',
     'p2p_fingerprint.py',
     'feature_uacomment.py',
     'feature_init.py',