scripted-diff: replace remaining Python test equality asserts

Some Python functional tests still use plain `assert x == y`.
The earlier commits convert the ambiguous assert patterns by hand, so this commit can rewrite the remaining safe cases mechanically.
The verify script excludes `wallet_bumpfee.py`, `test_framework/netutil.py`, and `test_framework/authproxy.py`, which still contain assert forms that the plain line-based substitution would misidentify.

-BEGIN VERIFY SCRIPT-
perl -pi -e 's/^(\s*)assert (.+?) == ([^,#]+?)$/\1assert_equal(\2, \3)/' $(git ls-files -- 'test/functional' \
':(exclude)test/functional/wallet_bumpfee.py' ':(exclude)test/functional/test_framework/netutil.py' ':(exclude)test/functional/test_framework/authproxy.py')
-END VERIFY SCRIPT-

test/functional/test_framework/test_node.py

@@ -226,7 +226,7 @@ class TestNode():
 
     def get_deterministic_priv_key(self):
         """Return a deterministic priv key in base58, that only depends on the node's index"""
-        assert len(self.PRIV_KEYS) == MAX_NODES
+        assert_equal(len(self.PRIV_KEYS), MAX_NODES)
         return self.PRIV_KEYS[self.index]
 
     def _node_msg(self, msg: str) -> str: