enable anchor_channels for regtest

* lower the final balance of the backup regtest, which is due to additional
  sweep transactions

* adapt ctx index

tests/regtest/regtest.sh

@@ -2,6 +2,8 @@
 export HOME=~
 set -eu
 
+TEST_ANCHOR_CHANNELS=True
+
 # alice -> bob -> carol
 
 alice="./run_electrum --regtest -D /tmp/alice"
@@ -89,6 +91,7 @@ if [[ $1 == "init" ]]; then
     rm -rf /tmp/$2/
     agent="./run_electrum --regtest -D /tmp/$2"
     $agent create --offline > /dev/null
+    $agent setconfig --offline enable_anchor_channels $TEST_ANCHOR_CHANNELS
     $agent setconfig --offline log_to_file True
     $agent setconfig --offline use_gossip True
     $agent setconfig --offline server 127.0.0.1:51001:t
@@ -169,7 +172,8 @@ if [[ $1 == "backup" ]]; then
     $alice request_force_close $channel1
     echo "request force close $channel2"
     $alice request_force_close $channel2
-    wait_for_balance alice 0.998
+    new_blocks 1
+    wait_for_balance alice 0.997
 fi
 
 
@@ -418,8 +422,16 @@ if [[ $1 == "breach_with_spent_htlc" ]]; then
     $alice load_wallet -w /tmp/alice/regtest/wallets/toxic_wallet
     # wait until alice has spent both ctx outputs
     echo "alice spends to_local and htlc outputs"
-    wait_until_spent $ctx_id 0
-    wait_until_spent $ctx_id 1
+    if [ $TEST_ANCHOR_CHANNELS = True ] ; then
+        # to_local_anchor/to_remote_anchor: 0 and 1 (both are present due to untrimmed htlcs)
+        # htlc: 2, to_local: 3
+        wait_until_spent $ctx_id 2
+        wait_until_spent $ctx_id 3
+    else
+        # htlc: 0, to_local: 1
+        wait_until_spent $ctx_id 0
+        wait_until_spent $ctx_id 1
+    fi
     new_blocks 1
     echo "bob comes back"
     $bob daemon -d
@@ -458,7 +470,12 @@ if [[ $1 == "watchtower" ]]; then
     ctx_id=$($bitcoin_cli sendrawtransaction $ctx)
     echo "alice breaches with old ctx:" $ctx_id
     echo "watchtower publishes justice transaction"
-    wait_until_spent $ctx_id 1  # alice's to_local gets punished immediately
+    if [ $TEST_ANCHOR_CHANNELS = True ] ; then
+        output_index=3
+    else
+        output_index=1
+    fi
+    wait_until_spent $ctx_id $output_index  # alice's to_local gets punished
 fi
 
 if [[ $1 == "just_in_time" ]]; then