Remove duplicata of broadcast txn from ChannelMonitor

Previously, if new ouputs were found to be watched as part
of channel operations, the block was rescan which triggers
again parser and generation of transactions already issued.

This commit first modifies the test framework without
altering further ChannelMonitor.

ChannelMonitor refactoring is introduced in a latter commit.

Author: Antoine Riard

lightning/src/ln/functional_test_utils.rs

@@ -35,6 +35,7 @@ use std::cell::RefCell;
 use std::rc::Rc;
 use std::sync::{Arc, Mutex};
 use std::mem;
+use std::collections::HashSet;
 
 pub const CHAN_CONFIRM_DEPTH: u32 = 100;
 pub fn confirm_transaction<'a, 'b: 'a>(notifier: &'a chaininterface::BlockNotifierRef<'b>, chain: &chaininterface::ChainWatchInterfaceUtil, tx: &Transaction, chan_id: u32) {
@@ -857,7 +858,7 @@ pub fn create_node_cfgs(node_count: usize) -> Vec<NodeCfg> {
 		let logger = Arc::new(test_utils::TestLogger::with_id(format!("node {}", i)));
 		let fee_estimator = Arc::new(test_utils::TestFeeEstimator { sat_per_kw: 253 });
 		let chain_monitor = Arc::new(chaininterface::ChainWatchInterfaceUtil::new(Network::Testnet, logger.clone() as Arc<Logger>));
-		let tx_broadcaster = Arc::new(test_utils::TestBroadcaster{txn_broadcasted: Mutex::new(Vec::new())});
+		let tx_broadcaster = Arc::new(test_utils::TestBroadcaster{txn_broadcasted: Mutex::new(Vec::new()), broadcasted_txn: Mutex::new(HashSet::new())});
 		let mut seed = [0; 32];
 		rng.fill_bytes(&mut seed);
 		let keys_manager = Arc::new(test_utils::TestKeysInterface::new(&seed, Network::Testnet, logger.clone() as Arc<Logger>));