[tests] fix nits.

Thanks to Marco Falke.

test/functional/test_framework/test_framework.py

@@ -255,8 +255,8 @@ class BitcoinTestFramework(object):
         except http.client.CannotSendRequest as e:
             self.log.exception("Unable to stop node")
         return_code = self.bitcoind_processes[i].wait(timeout=BITCOIND_PROC_WAIT_TIMEOUT)
-        assert_equal(return_code, 0)
         del self.bitcoind_processes[i]
+        assert_equal(return_code, 0)
 
     def stop_nodes(self):
         """Stop multiple bitcoind test nodes"""

test/functional/test_framework/util.py

@@ -203,9 +203,6 @@ def p2p_port(n):
 def rpc_port(n):
     return PORT_MIN + PORT_RANGE + n + (MAX_NODES * PortSeed.n) % (PORT_RANGE - 1 - MAX_NODES)
 
-def rpc_auth_pair(n):
-    return 'rpcuser💻' + str(n), 'rpcpass🔑' + str(n)
-
 def rpc_url(datadir, i, rpchost=None):
     rpc_u, rpc_p = get_auth_cookie(datadir, i)
     host = '127.0.0.1'