test: add rescan_utxos in MiniWallet's initialization

this simplifies usage when MiniWallet is used with a pre-mined chain.

test/functional/p2p_tx_privacy.py

@@ -53,7 +53,6 @@ class TxPrivacyTest(BitcoinTestFramework):
 
     def run_test(self):
         self.wallet = MiniWallet(self.nodes[0])
-        self.wallet.rescan_utxos()
 
         tx_originator = self.nodes[0].add_p2p_connection(P2PInterface())
         spy = self.nodes[0].add_p2p_connection(P2PTxSpy(), wait_for_verack=False)