test: rpc: add scanblocks functional test

Co-authored-by: James O'Beirne <james.obeirne@gmail.com>

test/functional/test_runner.py

@@ -316,6 +316,7 @@ BASE_SCRIPTS = [
     'rpc_deriveaddresses.py',
     'rpc_deriveaddresses.py --usecli',
     'p2p_ping.py',
+    'rpc_scanblocks.py',
     'rpc_scantxoutset.py',
     'feature_txindex_compatibility.py',
     'feature_unsupported_utxo_db.py',