test: create assert_not_equal util and add to where imports are needed

In the functional tests there are lots of cases where we assert != which
this new util will replace, we also are adding the imports and the new assertion

test/functional/rpc_orphans.py

@@ -19,6 +19,7 @@ from test_framework.messages import (
 from test_framework.p2p import P2PInterface
 from test_framework.util import (
     assert_equal,
+    assert_not_equal,
     assert_raises_rpc_error,
 )
 from test_framework.test_framework import BitcoinTestFramework
@@ -110,7 +111,7 @@ class OrphanRPCsTest(BitcoinTestFramework):
         assert tx_in_orphanage(node, tx_child_2["tx"])
 
         self.log.info("Check that orphan 1 and 2 were from different peers")
-        assert orphanage[0]["from"][0] != orphanage[1]["from"][0]
+        assert_not_equal(orphanage[0]["from"][0], orphanage[1]["from"][0])
         peer_ids = [orphanage[0]["from"][0], orphanage[1]["from"][0]]
 
         self.log.info("Unorphan child 2")