tests: Use explicit imports

test/functional/mempool_reorg.py

@@ -8,9 +8,9 @@ Test re-org scenarios with a mempool that contains transactions
 that spend (directly or indirectly) coinbase transactions.
 """
 
-from test_framework.test_framework import BitcoinTestFramework
 from test_framework.blocktools import create_raw_transaction
-from test_framework.util import *
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import assert_equal, assert_raises_rpc_error
 
 
 class MempoolCoinbaseTest(BitcoinTestFramework):