[test] explicitly check default -minrelaytxfee and -incrementalrelayfee

Github-Pull: #33106
Rebased-From:  1fbee5d7b6

test/functional/test_framework/mempool_util.py

@@ -20,6 +20,10 @@ from .wallet import (
 )
 
 ORPHAN_TX_EXPIRE_TIME = 1200
+# Default for -minrelaytxfee in sat/kvB
+DEFAULT_MIN_RELAY_TX_FEE = 1000
+# Default for -incrementalrelayfee in sat/kvB
+DEFAULT_INCREMENTAL_RELAY_FEE = 1000
 
 def assert_mempool_contents(test_framework, node, expected=None, sync=True):
     """Assert that all transactions in expected are in the mempool,