qa: port 12 wallet/mining tests to python3 and fix three framework blockers

Ports qa/rpc-tests from 6 python3 files to 18. Ran every ported test against
the freshly built v1.3.0 dragonxd. Results, honestly:

  PASS (1)            getblocktemplate_proposals.py
  NOT APPLICABLE (7)  wallet.py, walletbackup.py, wallet_protectcoinbase.py,
                      wallet_listnotes.py, wallet_mergetoaddress.py,
                      getblocktemplate.py, wallet_shieldcoinbase.py
  BLOCKED (4)         wallet_sapling, wallet_nullifiers, wallet_persistence,
                      wallet_treestate

The "not applicable" seven are inherited Zcash/Hush-era tests that exercise
features DragonX deliberately removed. They assume transparent t->t value
transfer, but ASSETCHAINS_PRIVATE=1 (hush_utils.h:1826) makes sendtoaddress
and sendmany consensus-refuse; they assume Sprout joinsplits, which are gone
from the RPC layer entirely; and they hardcode Bitcoin economics (10 coin/block,
100-block maturity) against DragonX's 3 DRGX and COINBASE_MATURITY=1. They are
ported and left in place rather than deleted, but they cannot pass on this chain
without being rewritten around z_shieldcoinbase/autoshield.

Three framework fixes in test_framework/util.py, each of which broke every
multi-node test:
  - initialize_chain() passed -connect=0, and init.cpp soft-sets -listen=0 when
    -connect is present, so cache node0 never opened its p2p port and nodes 1-3
    could never sync to it -- initialize_chain() hung forever in sync_blocks().
    Now passes -listen=1 -bind=127.0.0.1 -dnsseed=0 explicitly (an explicit arg
    beats SoftSetBoolArg) while keeping the cache nodes off the public network.
  - cache cleanup removed files from <datadir> when dragonxd writes them one
    level deeper into the net-specific <datadir>/regtest.
  - set_node_times() did print("..." + t) with t an int -> TypeError.
  - default binary paths corrected to src/dragonxd and src/dragonx-cli.

The four BLOCKED tests are blocked by a daemon assert, not by the port; see the
follow-up commit/report on BLOCK_VALID_CONTEXT.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FU87LdsJZiZkfq1eXubpeo

qa/rpc-tests/wallet_treestate.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python2
+#!/usr/bin/env python3
 # Copyright (c) 2016-2024 The Hush developers
 # Copyright (c) 2016 The Zcash developers
 # Distributed under the GPLv3 software license, see the accompanying
@@ -20,7 +20,16 @@ class WalletTreeStateTest (BitcoinTestFramework):
 
     # Start nodes with -regtestprotectcoinbase to set fCoinbaseMustBeProtected to true.
     def setup_network(self, split=False):
-        self.nodes = start_nodes(3, self.options.tmpdir, extra_args=[['-regtestprotectcoinbase','-debug=zrpc']] * 3 )
+        # -listen=1 and -dns=0 are DragonX-specific harness requirements, not part of the
+        # original test: start_node() passes -connect=0, which trips the "-connect set ->
+        # setting -listen=0" parameter interaction, so without -listen=1 the three nodes
+        # cannot open the p2p links connect_nodes_bi() asks for (node1/node2 stay at height
+        # 0 forever and sync_all() can never converge). -dns=0 blocks the unconditional
+        # node1..node10.dragonx.is -addnode injection in hush_args(), which otherwise dials
+        # the real DragonX seed nodes from regtest and floods these nodes with mainnet headers.
+        self.nodes = start_nodes(3, self.options.tmpdir,
+                                 extra_args=[['-regtestprotectcoinbase','-debug=zrpc',
+                                              '-listen=1','-dns=0']] * 3 )
         connect_nodes_bi(self.nodes,0,1)
         connect_nodes_bi(self.nodes,1,2)
         connect_nodes_bi(self.nodes,0,2)
@@ -28,7 +37,7 @@ class WalletTreeStateTest (BitcoinTestFramework):
         self.sync_all()
 
     def run_test (self):
-        print "Mining blocks..."
+        print("Mining blocks...")
 
         self.nodes[0].generate(100)
         self.sync_all()
@@ -79,7 +88,7 @@ class WalletTreeStateTest (BitcoinTestFramework):
         myopid = self.nodes[0].z_sendmany(myzaddr, recipients)
 
         # Wait for Tx 2 to begin executing...
-        for x in xrange(1, 60):
+        for x in range(1, 60):
             results = self.nodes[0].z_getoperationstatus([myopid])
             status = results[0]["status"]
             if status == "executing":