[tests] Add wallet-tool test

Original tests by João Barbosa <joao.paulo.barbosa@gmail.com>

Additional contribution by John Newbery <john@johnnewbery.com>

test/functional/test_runner.py

@@ -108,6 +108,7 @@ BASE_SCRIPTS = [
     'interface_bitcoin_cli.py',
     'mempool_resurrect.py',
     'wallet_txn_doublespend.py --mineblock',
+    'tool_wallet.py',
     'wallet_txn_clone.py',
     'wallet_txn_clone.py --segwit',
     'rpc_getchaintips.py',
@@ -562,7 +563,7 @@ class TestResult():
 def check_script_prefixes():
     """Check that test scripts start with one of the allowed name prefixes."""
 
-    good_prefixes_re = re.compile("(example|feature|interface|mempool|mining|p2p|rpc|wallet)_")
+    good_prefixes_re = re.compile("(example|feature|interface|mempool|mining|p2p|rpc|wallet|tool)_")
     bad_script_names = [script for script in ALL_SCRIPTS if good_prefixes_re.match(script) is None]
 
     if bad_script_names: